Utility of Fetal Humeral Length Measurements in Gestational Age Estimation in the Second and Third Trimesters in Pregnant Women Attending Antenatal Care Clinics in a Nigerian Tertiary Hospital: A Descriptive Cross-sectional Study

Utility of Fetal Humeral Length Measurements in Gestational Age Estimation in the Second and Third Trimesters in Pregnant Women Attending Antenatal Care Clinics in a Nigerian Tertiary Hospital: A Descriptive Cross-sectional Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Utility of Fetal Humeral Length Measurements in Gestational Age Estimation in the Second and Third Trimesters in Pregnant Women Attending Antenatal Care Clinics in a Nigerian Tertiary Hospital: A Descriptive Cross-sectional Study OLUCHI GERMAINE UMENZEKWE, KEVIN NWABUEZE EZIKE, OLUBUNMI OMOBOLANLE OLATUNJI, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9305071/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Background This study aims to evaluate the reliability of sonographic humeral length (HL) as a predictor of gestational age (GA), comparing its effectiveness to standard measurements like femur length (FL) and biparietal diameter (BPD). While the latter are routinely used, individual growth variations can cause discrepancies in measurements. The research explores if HL can help address these inconsistencies and offer a more comprehensive evaluation of fetal development. Methods This was a descriptive cross-sectional study that involved normal pregnant women with known first day of the last menstrual period (LMP), carrying normal singleton fetus in their second and third trimesters (14–40 weeks of GA). Grey scale ultrasound was used to measure the HL, FL and BPD to estimate the sonographic GA. Generated data was entered into a computer database and the statistical package for social sciences (SPSS) version 22.0 software Chicago, Illinois USA was used for analysis. Descriptive statistics were used to summarize continuous variables; Pearson’s correlation was used to test for relationships between continuous variables. Bland-Altman plot and paired t-test were used to identify any significant difference between measurements of GA by HL, FL and BPD Results This study involved 413 pregnant women in their 2nd and 3rd trimesters. Linear regression modelling was used to develop a formula for predicting gestational age with HL, predicted GA = 0.4917HL + 4.9487. Scatterplots with fitted regression lines showed a positive correlation between all measured fetal biometric parameters (HL and FL, BPD) and GA. A Bland-Altman plot was used to demonstrate the excellent agreement between HL and other routinely used parameters like FL and BPD. Conclusions This study demonstrated that fetal humeral length measurements were accurate alternatives to the conventional fetal biometric parameters such as FL and BPD. This can be applicable to certain conditions such as skeletal dysplasias, down syndrome, congenital anomalies, multiple gestation, engaged fetal head at term, breech positions and also when the growth of the femur may deviate due to environmental or genetic factors. humeral length femoral length biparietal diameter gestational age ultrasound Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Background Accurate prediction of the gestational age (GA) is very important in the management of obstetric patients for planning a timely and uneventful outcome. The use of ultrasound (US) as an imaging tool is pivotal in the estimation of fetal gestational age, evaluating fetal growth and general management of pregnancy from first trimester to delivery [ 1 ]. It is a convenient, relatively cheap, easy to operate, non-invasive and readily available imaging tool that uses non-ionizing radiation hence safe in pregnancy [ 2 ] Prior to the widespread use of US, clinicians relied on a combination of history and physical examination to clinically determine gestational age which typically includes menstrual cycle length, regularity and recall of first day of last menstrual period, unfortunately clinical history is usually not enough [ 3 , 4 ]. It has been reported that up to 45% of pregnant women are uncertain of menstrual dates because of poor recall, irregular cycles, bleeding in early pregnancy or oral contraceptive use within two months of conception [ 5 ]. The principle of use of ultrasound for biometric measurements assumes that the size of the embryo or fetus is consistent with gestational age [ 5 , 6 ]. In 1968, Campbell demonstrated that the midline echo of the fetus could be clearly seen from the thirteenth week of gestation and that second trimester cephalometry was a reliable method to identify pregnancy [ 7 ]. This heralded a new concept in prenatal medicine called “determination of gestational age by ultrasound’. He also developed the first fetal growth chart in the world illustrating biparietal diameter (BPD) changes from 13 to 40 weeks of gestation [ 8 ]. In 1975, Hansmann supplemented these examinations with abdominal circumference (AC) measurement taken at the level of the liver. Because the liver is a severely affected organ in intrauterine growth retardation (IUGR), the head circumference (HC) to abdominal circumference was introduced as a means of detecting brain spared IUGR fetus [ 9 ] Over the years, many US based antenatal assessment parameters have been studied to predict the correct GA at different stages of development/trimesters. They include BPD, HC, AC, and femur length (FL). Other indices, such as humeral length (HL), transcerebellar diameter, occipito-frontal diameter, clavicular length, orbital diameters, binocular distance, and foot length have also been used [ 10 ]. However, BPD, HC, AC, and FL are considered reliable predictors and are used as routine parameters in the second and third trimesters [ 11 ] The fetal HL is not widely used as a biometric parameter for determining GA although it is easy to be imaged with ultrasound and measured [ 12 ]. Nevertheless, we hypothesized that there is no significant difference between GA determined by HL and that obtained by FL. The purpose of this study, therefore, is to determine the GA of normal fetuses in the second and third trimesters by sonographic measurement of the HL in a Nigerian cohort of pregnant women attending the ante natal clinic of National Hospital, Abuja, Nigeria; and to assess its utility in the estimation of GA by comparing it with established US-based parameters such as BPD and FL. It is hoped that the outcome of this study will facilitate health system planning especially in the training and deployment of obstetric sonologists with limited technical ability who may find it easier to master GA estimation via HL measurements. Finally, the paucity of literature on this topic in our environment also makes the study worth doing to add to the body of knowledge. Methods Study location National Hospital Abuja is a 407-bed tertiary hospital located in the Central Area of Abuja, Nigeria’s federal capital. It serves as a referral center for Abuja and the neighboring states in North Central Nigeria. The department of radiology provides a wide range of radiological services including ultrasonography. Study design This study was a hospital-based descriptive cross-sectional study that was conducted in the department of radiology, National Hospital Abuja on a cohort of eligible patients referred for routine obstetric ultrasound scan in their second and third trimesters of pregnancy; carried out over a period of six months from February 2023 to July 2023. Sample size determination Sample size was calculated using the Fischer’s statistic formula: sample size = (Z2pq)/d2, where Z = Percentage of the standard normal distribution curve which defines 95% confidence interval of 1.96; P = prevalence rate from previous study; q = complimentary probability which is 1.0 – p; d = margin of error, which is 5% and equivalent to 0.05. The prevalence rate for normal population study of 50%, was used since no reasonable estimation of prevalence from previous study was available. Sample size: (1.96)2 x 0.5 (1.0–0.5)/ (0.05)2 = 384.16 However, allowing for attrition and concession to be made for percentage non-response of 10%, the final sample size was 413. Inclusion and exclusion criteria Inclusion Criteria Consenting patients, aged between 18 and 35 years, in their second and third trimester of singleton, uncomplicated pregnancies, who were sure of their last menstrual period (LMP); and not in labor at the time of examination were included in the study. The fetuses had to be without structural abnormalities and have intact membranes and normal amniotic fluid volumes. Exclusion Criteria Non-consenting patients, those below 18 and above 35 years old, and those with multiple gestations were excluded from the study. Patients with history of recurrent miscarriages; and those whose had conditions categorized as high risk, such as chronic hypertension, gestational diabetes mellitus, anemia, and hypothyroidism, were also excluded from the study. Patients whose fetuses had gross structural abnormalities; and whose gestational sacs had leaking or ruptured membranes, and/or inadequate or excess amniotic fluid volumes were also excluded. Equipment and procedures Equipment The US scans were performed using the general multipurpose Mindray ultrasound machine with a convex probe with low frequency range of 3.5MHz – 5.0MHz (DC-30 Model 75L38P, IPX7; Mindray bio-medical electronics, China Shenzhen, 2021). Examination Couch, clean bed linen with pillow, tissue paper, hand sanitizer and ultrasound coupling gels were also used. Procedures Each patient’s abdomen was initially scanned and sagittal, coronal, and transverse views through the fetus were obtained to confirm viability, lie, presentation, rule out multiple gestation and any gross fetal anomaly. The HL, FL and BPD and measurements were then obtained via the caliper method as follows: Longitudinal scanning through the fetal chest was done to identify and measure the humerus as the chest was identified with the heart beating. The measurement of humeral length was taken between two points at the ends of the bone diaphysis, disregarding any curvature. Three or more measurements were taken in each examination to obtain the accurate mean measurement [ 13 ]. The cartilage at the ends of the humerus were not included in the measurement. The body was measured between the epiphysis, which represents the portion of long bone formed by the primary ossification center. It appears as echogenic tubular structure in the arm, extending from the shoulder region to the elbow joint (Fig. 1 . Ultrasound measurement of fetal humeral length). Then the ultrasound was directed through the fetal pelvis to visualize the femur for measurement. Since the distal femur is usually flexed, the transducer was rotated from the position through 30–45 degrees towards the abdomen until the full length of the femur was visualized (Fig. 2 . Ultrasound measurement of fetal femoral length). The US beam was directed perpendicularly, along the long axis of the diaphysis of the bone and the diaphysis alone was measured after the hip and the knee were identified [ 14 ]. The cartilage at the ends of the femur was not included in the measurement [ 15 ]. The diaphysis was measured between the epiphysis, which represents the portion of the long bone formed by the primary ossification centers [ 16 ]. The femur appeared as a tubular echogenic structure in the thigh extending from the hip joint space to the knee joint (Fig. 2 ). Ultrasound measurement of fetal femoral length). The BPD was measured at the trans-thalamic plane with clear visualization of the thalami, the midline falx, and cavum septum pellucidum (CSP) as seen in Fig. 3 . The thalami are diencephalic hypoechoic structures located on either side of the midline [ 17 ]. The midline falx is seen as an echogenic line running antero-posteriorly in the midline bisecting the lateral ventricles while the CSP is seen anteriorly as an anechoic fluid filled space between the leaves of septum pellucidum. The calvaria appears as an oval echogenic structure which is smooth and symmetrical. BPD can be used for dating after 12 weeks. The BPD was measured from outer to inner edge of calvaria using calliper for tool (Fig. 3 ). Ultrasound measurement of fetal BPD ). The GA calculated from the LMP to the day of the ultrasound examination was taken as the known, control or standard menstrual age. Each parameter was compared with its standard chart and the accurate parameters noted for that known GA. (The standard GA was calculated by using the formula; The date of the ultrasound examination minus the date of the LMP) Statistical analysis Findings obtained from the obstetric patient’s sonographic examination reports were recorded in the data recording form. The generated data was entered into a computer database and the statistical package for social sciences (SPSS) version 22.0 software Chicago; Illinois USA was used for analysis. Descriptive statistics such as frequency, percentages, mean and standard deviation were used to summarize continuous variables. Pearson’s correlation was used to test relationships between continuous variables. Bland-Altman plot and paired t-test were used to identify any significant difference between measurements of GA by HL, FL and BPD. The results obtained were presented in tables, graphs and charts where necessary Results This study was conducted on 413 pregnant women between 14 to 40 weeks of gestation, attending their booking and antenatal clinic in their 2nd and 3rd trimesters in National hospital Abuja from February to July 2023. They were clinically considered to be undergoing an uneventful pregnancy and certain of the date of their LMP. The GA was calculated from the LMP up to the day of examination with ultrasound, and this was taken as standard menstrual age. HL, FL and BPD and were taken. The age of participants ranged between 18 and 35 years, with majority falling between the ages of 30 and 35 years 206 (49.9%). Their mean and standard deviation was 29.0 ± 3.6 years, the median was 29.0 years, and the 95% CI was 28.7–29.4 years (Fig. 4 ). A large proportion of the pregnant women were multiparous accounting for 181 (43.8%) while grand multipara were the least with a total of 14 (3.4%) as shown in Fig. 5 . The gestational age of participants assessed by LMP and USS were similar, with mean and standard deviations of 29.4 ± 7.6 and 29.5 ± 7.4 weeks respectively; and a median of 31 weeks each. Similarly, their 95% CIs were 28.7–30.2 and 28.8–30.2 weeks, respectively. Table 1 shows descriptive statistics for several ultrasound fetal biometry measurements taken from fetuses across different GA and it demonstrates that the mean and standard deviation for each of the measurements increases with GA. This implies the growth of the fetal humerus, head and femur with increasing GA over the course of pregnancy. The mean humeral length at 14 and 40 weeks was 15.2 ± 1.5 mm and 66.3 ± 2.4 mm respectively and the mean femoral length at 14 and 40 weeks was 14.1 ± 0.4 mm and 75.9 ± 2.5 mm respectively. It was observed that the mean humeral length increased gradually with increasing age from 15.2 ± 1.5 mm at 14 weeks to 66.3 ± 2.4 mm at 40 weeks. It was also observed that the femoral length gradually increased with an increase in GA from 14.1 ± 0.4 mm at 14 weeks to 75.9 ± 2.5 mm at 40 weeks. The mean BPD at 14 weeks and 40 weeks was 27.2 ± 1.4 mm and 97.1 ± 1.9 mm respectively Table 1 Mean value of fetal HL, FL and BPD from 14 to 40 weeks of gestation GA (Weeks) Frequency (%) HL Mean ± SD FL Mean ± SD BPD Mean ± SD 14 5(1.2) 15.2 ± 1.5 14.1 ± 0.4 27.2 ± 1.4 15 7(1.7) 18.0 ± 3.6 18.4 ± 2.8 30.8 ± 4.9 16 7(1.7) 20.5 ± 2.2 21.3 ± 2.7 34.5 ± 3.2 17 5(1.2) 23.0 ± 2.6 23.9 ± 3.2 37.5 ± 2.6 18 17(4.1) 25.5 ± 1.7 26.5 ± 1.8 40.4 ± 2.7 19 13(3.1) 29.0 ± 2.3 30.2 ± 2.1 46.4 ± 2.5 20 17(4.1) 32.1 ± 2.7 34.2 ± 3.2 48.6 ± 3.2 21 11(2.7) 32.4 ± 2.5 34.7 ± 2.5 50.8 ± 3.9 22 8(1.9) 35.8 ± 2.5 38.2 ± 3.3 53.3 ± 3.9 23 6(1.5) 39.6 ± 1.8 41.8 ± 2.0 58.0 ± 2.6 24 8(1.9) 41.8 ± 1.3 45.3 ± 1.4 62.4 ± 3.3 25 22(5.3) 43.2 ± 1.3 45.9 ± 2.5 61.6 ± 3.8 26 28(6.8) 43.6 ± 2.3 47.7 ± 2.7 64.5 ± 4.1 27 8(1.9) 48.1 ± 2.3 51.8 ± 3.4 71.4 ± 2.3 28 11(2.7) 48.2 ± 3.4 54.1 ± 1.2 74.9 ± 3.5 29 13(3.1) 49.7 ± 2.7 54.1 ± 3.3 72.8 ± 3.5 30 13(3.1) 51.9 ± 1.9 58.9 ± 2.7 75.5 ± 3.1 31 14(3.4) 55.1 ± 0.8 62.3 ± 2.1 81.1 ± 2.9 32 23(5.6) 56.4 ± 1.8 62.4 ± 1.3 81.3 ± 1.7 33 14(3.4) 57.6 ± 1.2 63.5 ± 2.0 84.3 ± 1.9 34 14(3.4) 59.5 ± 2.3 67.4 ± 2.4 86.1 ± 2.6 35 17(4.1) 60.9 ± 2.1 67.7 ± 3.3 87.1 ± 1.9 36 18(4.4) 63.2 ± 1.4 71.6 ± 1.4 91.5 ± 9.5 37 41(9.9) 64.6 ± 1.8 72.9 ± 1.8 92.1 ± 2.2 38 45(10.9) 65.4 ± 1.5 74.0 ± 2.2 93.1 ± 3.6 39 16(3.9) 66.2 ± 1.3 74.9 ± 1.7 94.1 ± 2.1 40 12(2.9) 66.3 ± 2.4 75.9 ± 2.5 97.1 ± 1.9 HL= Humeral length FL= Femoral Length BPD = Biparietal diameter SD = Standard deviation GA = Gestational age Figure 6 shows a scatter plot of humeral length (mm) versus gestational age (weeks). The data points are generally clustered along a positive trend line, indicating that there is a positive correlation between humeral length and gestational age with a coefficient of 0.988. This is statistically significant with a p-value of < 0.001. The regression line is described by the equation USS = 0.4917HL + 4.9487 Figure 7 shows a positive linear correlation between the two variables, implying that as GA increases, The FL also increases. The plot shows a high degree of correlation with a coefficient of 0.990, meaning that the relationship between the two variable is strong. It is statistically significant with a p-value of < 0.001. The regression line is described by the equation USS = 0.414FL + 6.6023 Figure 8 shows a positive linear correlation between the two variables, implying that as GA increases, the BPD also increases. The plot shows a high degree of correlation with a coefficient of 0.983, meaning that the relationship between the two variable is strong. It is statistically significant with a p-value of < 0.001. The regression line is described by the equation USS = 0.367BPD + 2.778 Table 2 presents the results of a multiple linear regression analysis with various fetal biometric measurements as predictors of gestational age. The coefficients represent the estimated change in gestational age for a one-unit increase in each predictor, holding all other variables constant. The standard error (SE) indicates the precision of the coefficient estimates, while the t-statistic and p-value assess the significance of each predictor. The results show that FL, BPD, and HL are all significantly associated with gestational age, as indicated by their t-statistics and p-values. Table 2 Multiple Linear Regression Showing the Relationship Between Predictor Variables and Gestational Age by USS Predictors Coefficient Standard Error t-statistics P-value Constant 5.185 0.226 22.912 < 0.001* HL (mm) 0.090 0.030 2.946 0.003* FL (mm) 0.240 0.025 9.598 < 0.001* BPD (mm) 0.090 0.014 6.576 < 0.001* *Significant at 95% Figures 9 and 10 show Bland-Altman plots assessing the agreement between humeral length gestational age (HLGA) and femoral length gestational age (FLGA) on one hand, and biparietal diameter gestational age (BPDGA) on the other. There was no significant bias between HLGA and FLGA, with a mean difference of 0.042 and limits of agreement of -2.6589 and 2.7843 indicating that humeral length is a reliable measure for estimating gestational age. There was also no significant bias between the humeral length gestational age (HLGA) and biparietal diameter gestational age (BPDGA), with a mean difference of -0.0654 and limits of agreement of -2.5068 and 2.3759 indicating that humeral length is a reliable measure for estimating gestational age (Fig. 10 ). Figure 11 is a correlation matrix revealing a strong positive relationship among the fetal biophysical parameters: Humeral Length Gestational Age (HLGA), Femur Length Gestational Age (FLGA) and Biparietal Diameter Gestational Age (BPDGA). All correlation coefficients are equal to or greater than 0.98, indicating that the gestational age estimates derived from these parameters are highly consistent and reliable in assessing fetal growth. The strongest correlations are observed between BPDGA and HLGA (r = 0.986). Discussion Women are fertile between menarche and menopause, but the peak reproductive ages are from 18–29 years [ 18 ]. A recent trend however shows that the predominant biological reproductive span of women ranges from 30.9–39.3 years [ 19 ]. In keeping with this trend, the majority (49.9%) of the participants in our study were in the 30–35 years age range. The majority of participants in our study (47.2%) were multiparous, consistent with the findings of 40% reported by Maharaj et al. in Fiji but lower than the 67.9% reported by Saliu et al. in Kano, Nigeria [ 20 , 21 ]. The reasons for this same-country variation are unclear but could be attributed to heterogeneity of population in Abuja, the location of the index study, which being more cosmopolitan has more variety in educational status, cultural norms and beliefs, and more awareness of and greater access to modern contraceptive methods which influence family size. The mean maternal age in the index study of 29.0 ± 3.6 years similar to 29 ± 6 years reported by Saliu et al. in Kano, Nigeria; 28.3 years by Yazdani et al in Sweden; and 28.7 years by Benzies et al in the Netherlands [ 21 , 22 , 23 ]. This trend of increased age of onset of biological reproductive span and prevalence of multiparity among women of advanced maternal age reflects a shift in reproductive behavior, with women choosing to have children later in life but often completing their families within a shorter time frame [ 19 ]. First trimester ultrasound measurement of CRL remain the standard, most accurate method for estimating fetal age, however second and third trimester ultrasound measurements of BPD, HC, AC, and FL are also methods [ 24 ]. In the current study, ultrasound measurements of fetal HL, FL and BPD, all demonstrated an expected linear relationship with advancing gestational age between 14–40 weeks. The observed means and standard deviations for each parameter align closely with fetal growth trajectories documented in previous literature [ 25 , 26 ]. HL measurements are not routinely used in fetal GA estimation, however in this study linear regression modelling allowed the development of a population specific formula for predicting GA based on sonographic measurement of fetal HL. The regression coefficient of 0.4917 and constant intercept of 4.949 weeks obtained in our study aligns with the regression coefficient of 0.5213 and constant intercept of 4.905 weeks reported by Mital et al in India [ 27 ]. It provides external validation of the linear relationship between advancing gestational age and longitudinal humeral growth. Overall, the excellent agreement in HL regression slopes affirms that humeral length is a strong and reliable predictor of gestational age across populations. Scatterplots with fitted regression lines and regression equations were created to observe the relationships between gestational age by USS and HL, FL and BPD respectively. HL, FL and BPD regression lines were positively related to the GA, in keeping with similar studies by Mounika et al., Aggarwal et al., and Adiri et al. who observed similar associations while the regression equations were different [ 28 , 29 , 30 ]. The disparity in regression equations may be due to variations caused by several factors such as race, socioeconomic status, genetics, geographical location, and associated maternal diseases [ 30 ]. Multiple linear regression analysis was also performed, which revealed HL, FL and BPD were all statistically significant predictors of GA. Bland-Altman plots were created to compare the gestational age derived from HL and that derived from FL and BPD. All the Bland-Altman plots showed that most of the points were within the limits of agreement, indicating that HL is a reliable measure for estimating GA. This finding is similar to those from studies carried out by Patre et al., Mital et al., Gamerradin et al., and Hassan [ 26 , 27 , 31 , 32 ]. Despite these positive correlations with the more commonly used fetal biometric parameters, HL is not as widely used or recognized as a primary biometric parameter for estimating gestational age. This may be because the routinely used fetal biometry parameters are usually reliable. In conditions where their reliability fails or reduces, HL can serve as an additional parameter to increase accuracy. Nevertheless, it is often recommended to use multiple biometric parameters together for more accurate estimations [ 5 ]. Variability in fetal growth patterns, the influence of factors such as ethnicity and maternal health can also affect the accuracy of humeral length limiting its utility as a standalone measure [ 30 , 32 ]. Limitations The major limitation of this study was that it was hospital-based and, therefore, analyzed only the parameters of participants who accessed antenatal care at our center. Accordingly, the findings may not be wholly representative of the general population. Another limitation was that the data was collected at a single time point rather than following fetuses longitudinally across gestation. This limits characterization of individualized growth trajectories. Finally, the restriction of age range of participants to 18–35 years meant that our findings may not accurately assess women outside that age bracket. Conclusions This study shows that ultrasonographic measurement of fetal HL provides a reliable and accurate estimate of GA in singleton pregnancies comparable to measurements of FL and BPD. The maternal age of participants did not affect the reliability of these measurements. Furthermore, the strong linear association between increasing gestational age and increasing HL reflects the normal pattern of longitudinal bone development in the uterus. When in doubt of the accuracy of routine parameters especially in cases of hydrocephalus, anencephaly, multiple gestation, and term pregnancy with engaged head or breech positions, HL should be employed as an alternative and reliable option. Abbreviations IUGR Intrauterine Growth Restriction LMP Last Menstrual Period MHz Mega Hertz US Ultrasound CI Confidence interval EDD Expected Delivery Date CRL Crown rump length GSD Gestational sac diameter GA Gestational Age AC Abdominal circumference BPD Biparietal diameter FL Femur Length HC Head circumference HL Humeral Length FLGA Ultrasound gestational age by Femur length HLGA Ultrasound gestational age by Humeral length BPDGA Ultrasound gestational age by Biparietal diameter HREC Health Research Ethics Committee Declarations Ethics and consent to participate Ethical approval was duly obtained from Health Research Ethics Committee (HREC) of National Hospital Abuja via NHA/ADMIN/236/V.VII/. Informed consent was obtained from participants. Consent for publication Not applicable. Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author (Oluchi Germaine Umenzekwe) on reasonable request. Competing interests The authors declare that they have no competing interests Funding No funding to report Contributions OGU is the principal and corresponding author. KNE put forward important revision suggestions and made corresponding modifications for this article. All authors contributed to the article and approved the submitted version. Acknowledgements The authors give thanks to all participants who volunteered to participate in this study. References Lee LH, Bradburn E, Craik R, Yaqub M, Norris SA, Ismail LC, et al. Machine learning for accurate estimation of fetal gestational age based on ultrasound images. NPJ Digit Med. 2023;6:36. Basilico R, Pizzi AD, Mincuzzi E, Danzi R, Ricciardulli A, Grzycka-Kowalczyk L. Non-traumatic Abdominal and Pelvic Emergencies in Pregnant Patients: Role of Ultrasound. In: Patlas MN, Katz DS, Scaglione M, editors. Emergency Imaging of Pregnant Patients [Internet]. Cham: Springer International Publishing; 2020. pp. 63–85. Available from: https://doi.org/10.1007/978-3-030-42722-1_4 , Accessed 4 Feb 2024. Naidu K, Fredlund KL. Gestational Age Assessment. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. Available from: http://www.ncbi.nlm.nih.gov/books/NBK526000/ . Accessed 4 Feb 2024. Kalish RB, Chervenak FA. Sonographic determination of gestational age. Ultrasound Rev Obstet Gynecol. 2005;5(4):254–8. Butt K, Lim KI. Guideline 388-Determination of Gestational Age by Ultrasound. J Obstet Gynaecol Can. 2019;41(10):1497–507. Salomon Lj, Alfirevic Z, Da Silva Costa F, Deter Rl, Figueras F, Ghi T, et al. ISUOG Practice Guidelines: ultrasound assessment of fetal biometry and growth. Ultrasound Obstet Gynecol. 2019;53(6):715–23. Campbell S. An improved method of fetal cephalometry by ultrasound. J Obstet Gynaecol Br Commonw. 1968;75(5):568–76. Campbell S. The prediction of fetal maturity by ultrasonic measurement of the biparietal diameter. J Obstet Gynaecol Br Commonw. 1969;76(7):603–9. Izadifar Z, Izadifar Z, Chapman D, Babyn P. An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications. J Clin Med. 2020;9(2):460. Garg A, Habeebullah S, Rathod S. Comparison of Ultrasonic Measurement of Fetal Kidney Length with Other Fetal Biometric Indices in Determining Gestational Age in Third Trimester in South Indian Population. J South Asian Feder Obst Gynae. 2022;14(5):587–91. Žaliūnas B, Bartkevičienė D, Drąsutienė G, Utkus A, Kurmanavičius J. Fetal biometry: Relevance in obstetrical practice. Medicina. 2017;53(6):357–64. Rao BRC, Sreepadma S, Associate, Professor, Department of Anatomy, SDM College of Medical SciencesHospital, Dharwad, Karnataka, India., Kalghatgi RN. The Study of Relation Between Gestational Age of Human Fetuses and the Diaphyseal Length of Femur usin Ultrasonography. IJAR. 2017;5(1.1):3342–3349. Lees CC, Stampalija T, Baschat AA, Da Silva Costa F, Ferrazzi E, Figueras F, et al. ISUOG Practice Guidelines: diagnosis and management of small-for‐gestational‐age FETUS and fetal growth restriction. Ultrasound Obstet Gyne. 2020;56(2):298312. Alzubaidi M, Agus M, Alyafei K, Althelaya KA, Shah U, Abd-Alrazaq A, et al. Toward deep observation: A systematic survey on artificial intelligence techniques to monitor FETUS via ultrasound images. iScience. 2022;25(8):104713. Deter RL, Lee W, Yeo L, Erez O, Ramamurthy U, Naik M, et al. Individualized growth assessment: conceptual framework and practical implementation for the evaluation of fetal growth and neonatal growth outcome. Am J Obstet Gynecol. 2018;218(Suppl 2):656–78. Procas-Ramon B, Hierro-Espinosa C, Salim I, Impey L, Ioannou C. The impact of individual sonographer variation on the detection of small for gestational age Fetuses using a third trimester growth scan. J Clin Ultrasound. 2021;49(5):442–50. Thalamus [Internet]. http://www.fetalultrasound.com/online/text/100-089.HTM . Accessed 23 Sep 2023. Having. April a baby after age 35 – how aging affects fertility and pregnancy [Internet]. https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy# . Accessed 1 2026. Nabhan AF, Mburu G, Elshafeey F, Magdi R, Kamel M, Elshebiny M, Abuelnaga YG, Ghonim M, Abdelhamid MH, Ghonim M, Eid P, Morsy A, Nasser M, Abdelwahab N, Elhayatmy F, Hussein AA, Elgabaly N, Sawires E, Tarkhan Y, Doas Y, Farrag N, Amir A, Gobran MF, Maged M, Abdulhady M, Sherif Y, Dyab M, Kiarie J. Women's reproductive span: a systematic scoping review. Hum Reprod Open. 2022;2hoac005. 10.1093/hropen/hoac005 . Maharaj R, Mohammadnezhad M. Perception of pregnant women towards early antenatal visit in Fiji: a qualitative study. BMC Pregnancy Childbirth. 2022;22(1):111. Saliu MA, Salihu A, Mada SB, Owolabi OA. Dyslipidaemia-related cardiovascular risk among pregnant women attending Aminu Kano Teaching Hospital Kano: A longitudinal study. J Taibah Univ Med Sci. 2021;16(6):870–7. Yazdani M, Amirshahi E, Shakeri A, Amirshahi R, Malekmakan L. Prenatal and Maternal Outcomes in Advanced Maternal Age, a Comparative Study. Women’s Health Bull. 2015;2(2):1–5. Benzies KM. Advanced maternal age: Are decisions about the timing of child-bearing a failure to understand the risks? CMAJ. 2008;178(2):183–4. Kunarathnam V, Tafti D. Sonography Assessment of Gestational Age. [Updated 2026 Feb 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK570610/ . Accessed 1 April 2026. Kumar S, Pandey VD, Yogesh Y. Fetal humerus Length for Prediction of Gestational Age: An Ultrasonographic Study. JMSCR. 2018;6(12):171–6. Patre V, Aryan AK, Sahu P, Patre V. Ultrasonographic Evaluation of Fetal Humerus Length for Assessment of Gestational Age and Its Comparison with Other Conventional Parameters. Int J Sci Stud. 2015;3(7):58–64. Mital P, Ainani R, Hooja N, Sonkhya P, Pradodh V, Chaudhary K, et al. A cross-sectional study to evaluate sonographic fetal humerus length for estimation of gestational age in normal singleton pregnancies at a tertiary care centre. Int J Reprod Contracept Obstet Gynecol. 2019;8(9):3622–9. Hammed MV, Mallikarjunappa A, Revathi RB, Parimal M. Ultrasonographic Evaluation Of Fetal Humerus Length For Assessment Of Gestational Age And Its Comparison With Other Conventional Parameters. Int J Sci Res. 2019;8(12):9–11. Aggarwal N, Sharma GL. Fetal ultrasound parameters: Reference values for a local perspective. Indian J Radiol Imaging. 2020;30(2):149–55. Adiri CO, Anyanwu GE, Agwuna KK, Obikili EN, Ezugworie OJ, Agu AU, et al. Use of fetal biometry in the assessment of gestational age in South East Nigeria: Femur length and biparietal diameter. Niger J Clin Pract. 2015;18(4):477–82. Gameraddin M, Abdelmaboud S, Alshoabi S. The role of fetal humeral length in determination of gestational age compared with femoral length using ultrasonography. IOSR-JDMS. 2015;14(5):65–8. Hassan MG. Humeral Length versus Femur Length for Estimating Fetal Age in the Third Trimester Using Ultrasound among Saudi fetuses. J Med Ultrasound. 2022;31(2):133–6. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 20 May, 2026 Reviews received at journal 19 May, 2026 Reviewers agreed at journal 09 May, 2026 Reviewers invited by journal 08 May, 2026 Editor assigned by journal 16 Apr, 2026 Editor invited by journal 13 Apr, 2026 Submission checks completed at journal 08 Apr, 2026 First submitted to journal 08 Apr, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9305071","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":640995153,"identity":"5f103e34-35e5-4579-a341-962e27752857","order_by":0,"name":"OLUCHI GERMAINE UMENZEKWE","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABFElEQVRIiWNgGAWjYDCCAxCKBy7ADyISCkjRItkA0mJAWAsCGIBF8Gjhu3384uPKHDsZc/Ye0w0fd9TJGZ9fnfjhgQGDPL8YhnEQZ5zLKTY8uy2Zx7LnjNnNmWfYjM1uvN0sAXSY4czZCVi1GJzhSZNs3MbMY3Ajx+w2bxtP4rYbZzeAtCQY3MapJf1n47Z6HoP7b8xu/22TqN884+zmH/i1sB9jbNx2GGgLj9ltxjaDBAP+3m14bZE8w8MMdNhxHoMzaWU3e9sSDGfc4N1mkWAggdMvfGfYH35s3FZtb3D88LYbP9vq5Pn7z26++aPCRp5fGrsWYCSiR4EEWKUEDuUgwP4ATYD/AB7Vo2AUjIJRMBIBANjlZMXq+X2eAAAAAElFTkSuQmCC","orcid":"","institution":"Federal Medical Centre","correspondingAuthor":true,"prefix":"","firstName":"OLUCHI","middleName":"GERMAINE","lastName":"UMENZEKWE","suffix":""},{"id":640995154,"identity":"614bee7f-af7f-4bb6-811e-20431bf602a3","order_by":1,"name":"KEVIN NWABUEZE EZIKE","email":"","orcid":"","institution":"NILE UNIVERSITY OF NIGERIA","correspondingAuthor":false,"prefix":"","firstName":"KEVIN","middleName":"NWABUEZE","lastName":"EZIKE","suffix":""},{"id":640995155,"identity":"a0488241-d7f2-41cd-b0aa-4a75ce740716","order_by":2,"name":"OLUBUNMI OMOBOLANLE OLATUNJI","email":"","orcid":"","institution":"NATIONAL HOSPITAL ABUJA","correspondingAuthor":false,"prefix":"","firstName":"OLUBUNMI","middleName":"OMOBOLANLE","lastName":"OLATUNJI","suffix":""},{"id":640995156,"identity":"e8a03000-1c33-4c24-b623-c4fd0294336b","order_by":3,"name":"AISHAT BOLANLE AKINTOBI","email":"","orcid":"","institution":"NATIONAL HOSPITAL ABUJA","correspondingAuthor":false,"prefix":"","firstName":"AISHAT","middleName":"BOLANLE","lastName":"AKINTOBI","suffix":""},{"id":640995157,"identity":"016a9c40-8ebe-46ad-8ded-41bc169c8064","order_by":4,"name":"FEYISAYO YVONNE DAJI","email":"","orcid":"","institution":"NATIONAL HOSPITAL ABUJA","correspondingAuthor":false,"prefix":"","firstName":"FEYISAYO","middleName":"YVONNE","lastName":"DAJI","suffix":""},{"id":640995158,"identity":"548841a2-b2c1-4229-8d01-4dfd8df1d11a","order_by":5,"name":"EMMANUEL OLABODE ABORISADE","email":"","orcid":"","institution":"JOH-JOSH LLC","correspondingAuthor":false,"prefix":"","firstName":"EMMANUEL","middleName":"OLABODE","lastName":"ABORISADE","suffix":""},{"id":640995159,"identity":"cdce7257-fbcc-469b-8a88-f6113bc2053f","order_by":6,"name":"RAMON OLUSHOLA WAHAB","email":"","orcid":"","institution":"LAGOS UNIVERSITY TEACHING HOSPITAL","correspondingAuthor":false,"prefix":"","firstName":"RAMON","middleName":"OLUSHOLA","lastName":"WAHAB","suffix":""}],"badges":[],"createdAt":"2026-04-02 15:38:43","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9305071/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9305071/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":109762932,"identity":"e1662b01-feb1-4fc2-9f8d-5aaec11f3c5e","added_by":"auto","created_at":"2026-05-22 07:32:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":654689,"visible":true,"origin":"","legend":"\u003cp\u003eUltrasound measurement of fetal humeral length\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/dd10180e14d9c83d9c0b799a.png"},{"id":109764972,"identity":"e283a374-5215-4f8c-9698-470e269ce1b5","added_by":"auto","created_at":"2026-05-22 07:38:48","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6049089,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUltrasound measurement of fetal femoral length\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/02147857a909b255fb06f6aa.png"},{"id":109762929,"identity":"eb2f35a7-23a0-469e-9140-18be9e5c2b2b","added_by":"auto","created_at":"2026-05-22 07:32:53","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1478090,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eUltrasound measurements of fetal BPD\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/7aea6ad7307075b4fb49ad99.png"},{"id":109765082,"identity":"74066f38-fe19-4840-b887-8f78f7c352ff","added_by":"auto","created_at":"2026-05-22 07:39:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":504145,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eAge distribution of participants\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/bc2a3d01c7388d5b15c32116.png"},{"id":109764892,"identity":"fda1bfa7-7ce7-482e-b8a2-303b100d795a","added_by":"auto","created_at":"2026-05-22 07:38:24","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":776039,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eParity of participants\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/6f6d5a4487e591628c94226b.png"},{"id":109762933,"identity":"1a4006d4-53d3-4fc6-892f-d06ff864db6b","added_by":"auto","created_at":"2026-05-22 07:32:56","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":89998,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScatter Plot Showing the Relationship Between Gestational Age and Humeral Length By USS\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/412d09437778d779565124cc.png"},{"id":109763740,"identity":"72792877-afe7-4079-93ff-e2f84e2df0e3","added_by":"auto","created_at":"2026-05-22 07:35:41","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":835549,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScatter Plot Showing the Relationship Between Femur Length and Gestational Age by USS\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/0c4349a506ce14620c7e2c8b.png"},{"id":109764774,"identity":"ebd1b000-5da8-425c-bb39-10b292aefab4","added_by":"auto","created_at":"2026-05-22 07:38:02","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":802099,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eScatter Plot Showing the Relationship Between Biparietal Diameter and Gestational Age by USS\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/8b9995ac375406e8cb24a14e.png"},{"id":109763625,"identity":"7bd0a96a-c85b-462c-9d36-730b8c00854f","added_by":"auto","created_at":"2026-05-22 07:35:09","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":261193,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBland-Altman Plot Showing the Agreement Between HLGA and FLGA\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage9.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/39b41fa2e88bef8aebc184c2.png"},{"id":109763662,"identity":"326e43cb-525a-4687-a0dc-f09226828272","added_by":"auto","created_at":"2026-05-22 07:35:22","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":268746,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA Bland-Altman plot to assess the agreement between HLGA and BPDGA\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"floatimage10.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/398071dbf982a3f85aedf6bb.png"},{"id":109762930,"identity":"1794bbab-1f89-466f-b4d1-e9417c2e0ef4","added_by":"auto","created_at":"2026-05-22 07:32:53","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":733395,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation matrix revealing a strong positive relationship among the fetal biophysical parameters\u003c/p\u003e","description":"","filename":"floatimage11.png","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/c41d3eb7e8ffd8cabb504303.png"},{"id":109766501,"identity":"55c68acf-a31a-463b-b02d-0f441d549a70","added_by":"auto","created_at":"2026-05-22 07:46:04","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":12706443,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9305071/v1/0d5d2878-15c2-4931-8e27-4fab363611bb.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Utility of Fetal Humeral Length Measurements in Gestational Age Estimation in the Second and Third Trimesters in Pregnant Women Attending Antenatal Care Clinics in a Nigerian Tertiary Hospital: A Descriptive Cross-sectional Study","fulltext":[{"header":"Background","content":"\u003cp\u003eAccurate prediction of the gestational age (GA) is very important in the management of obstetric patients for planning a timely and uneventful outcome. The use of ultrasound (US) as an imaging tool is pivotal in the estimation of fetal gestational age, evaluating fetal growth and general management of pregnancy from first trimester to delivery [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It is a convenient, relatively cheap, easy to operate, non-invasive and readily available imaging tool that uses non-ionizing radiation hence safe in pregnancy [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/p\u003e \u003cp\u003ePrior to the widespread use of US, clinicians relied on a combination of history and physical examination to clinically determine gestational age which typically includes menstrual cycle length, regularity and recall of first day of last menstrual period, unfortunately clinical history is usually not enough [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. It has been reported that up to 45% of pregnant women are uncertain of menstrual dates because of poor recall, irregular cycles, bleeding in early pregnancy or oral contraceptive use within two months of conception [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe principle of use of ultrasound for biometric measurements assumes that the size of the embryo or fetus is consistent with gestational age [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In 1968, Campbell demonstrated that the midline echo of the fetus could be clearly seen from the thirteenth week of gestation and that second trimester cephalometry was a reliable method to identify pregnancy [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. This heralded a new concept in prenatal medicine called \u0026ldquo;determination of gestational age by ultrasound\u0026rsquo;. He also developed the first fetal growth chart in the world illustrating biparietal diameter (BPD) changes from 13 to 40 weeks of gestation [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. In 1975, Hansmann supplemented these examinations with abdominal circumference (AC) measurement taken at the level of the liver. Because the liver is a severely affected organ in intrauterine growth retardation (IUGR), the head circumference (HC) to abdominal circumference was introduced as a means of detecting brain spared IUGR fetus [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eOver the years, many US based antenatal assessment parameters have been studied to predict the correct GA at different stages of development/trimesters. They include BPD, HC, AC, and femur length (FL). Other indices, such as humeral length (HL), transcerebellar diameter, occipito-frontal diameter, clavicular length, orbital diameters, binocular distance, and foot length have also been used [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. However, BPD, HC, AC, and FL are considered reliable predictors and are used as routine parameters in the second and third trimesters [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe fetal HL is not widely used as a biometric parameter for determining GA although it is easy to be imaged with ultrasound and measured [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Nevertheless, we hypothesized that there is no significant difference between GA determined by HL and that obtained by FL. The purpose of this study, therefore, is to determine the GA of normal fetuses in the second and third trimesters by sonographic measurement of the HL in a Nigerian cohort of pregnant women attending the ante natal clinic of National Hospital, Abuja, Nigeria; and to assess its utility in the estimation of GA by comparing it with established US-based parameters such as BPD and FL. It is hoped that the outcome of this study will facilitate health system planning especially in the training and deployment of obstetric sonologists with limited technical ability who may find it easier to master GA estimation via HL measurements. Finally, the paucity of literature on this topic in our environment also makes the study worth doing to add to the body of knowledge.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy location\u003c/h2\u003e \u003cp\u003eNational Hospital Abuja is a 407-bed tertiary hospital located in the Central Area of Abuja, Nigeria\u0026rsquo;s federal capital. It serves as a referral center for Abuja and the neighboring states in North Central Nigeria. The department of radiology provides a wide range of radiological services including ultrasonography.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eStudy design\u003c/h3\u003e\n\u003cp\u003eThis study was a hospital-based descriptive cross-sectional study that was conducted in the department of radiology, National Hospital Abuja on a cohort of eligible patients referred for routine obstetric ultrasound scan in their second and third trimesters of pregnancy; carried out over a period of six months from February 2023 to July 2023.\u003c/p\u003e\n\u003ch3\u003eSample size determination\u003c/h3\u003e\n\u003cp\u003eSample size was calculated using the Fischer\u0026rsquo;s statistic formula: sample size = (Z2pq)/d2, where Z\u0026thinsp;=\u0026thinsp;Percentage of the standard normal distribution curve which defines 95% confidence interval of 1.96; P\u0026thinsp;=\u0026thinsp;prevalence rate from previous study; q\u0026thinsp;=\u0026thinsp;complimentary probability which is 1.0 \u0026ndash; p;\u003c/p\u003e \u003cp\u003ed\u0026thinsp;=\u0026thinsp;margin of error, which is 5% and equivalent to 0.05.\u003c/p\u003e \u003cp\u003eThe prevalence rate for normal population study of 50%, was used since no reasonable estimation of prevalence from previous study was available.\u003c/p\u003e \u003cp\u003eSample size: (1.96)2 x 0.5 (1.0\u0026ndash;0.5)/ (0.05)2\u0026thinsp;=\u0026thinsp;384.16\u003c/p\u003e \u003cp\u003eHowever, allowing for attrition and concession to be made for percentage non-response of 10%, the final sample size was 413.\u003c/p\u003e\n\u003ch3\u003eInclusion and exclusion criteria\u003c/h3\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eInclusion Criteria\u003c/h2\u003e \u003cp\u003eConsenting patients, aged between 18 and 35 years, in their second and third trimester of singleton, uncomplicated pregnancies, who were sure of their last menstrual period (LMP); and not in labor at the time of examination were included in the study. The fetuses had to be without structural abnormalities and have intact membranes and normal amniotic fluid volumes.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eExclusion Criteria\u003c/h2\u003e \u003cp\u003eNon-consenting patients, those below 18 and above 35 years old, and those with multiple gestations were excluded from the study. Patients with history of recurrent miscarriages; and those whose had conditions categorized as high risk, such as chronic hypertension, gestational diabetes mellitus, anemia, and hypothyroidism, were also excluded from the study. Patients whose fetuses had gross structural abnormalities; and whose gestational sacs had leaking or ruptured membranes, and/or inadequate or excess amniotic fluid volumes were also excluded.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEquipment and procedures\u003c/h3\u003e\n\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eEquipment\u003c/h2\u003e \u003cp\u003eThe US scans were performed using the general multipurpose Mindray ultrasound machine with a convex probe with low frequency range of 3.5MHz \u0026ndash; 5.0MHz (DC-30 Model 75L38P, IPX7; Mindray bio-medical electronics, China Shenzhen, 2021). Examination Couch, clean bed linen with pillow, tissue paper, hand sanitizer and ultrasound coupling gels were also used.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eProcedures\u003c/h2\u003e \u003cp\u003eEach patient\u0026rsquo;s abdomen was initially scanned and sagittal, coronal, and transverse views through the fetus were obtained to confirm viability, lie, presentation, rule out multiple gestation and any gross fetal anomaly. The HL, FL and BPD and measurements were then obtained via the caliper method as follows:\u003c/p\u003e \u003cp\u003eLongitudinal scanning through the fetal chest was done to identify and measure the humerus as the chest was identified with the heart beating. The measurement of humeral length was taken between two points at the ends of the bone diaphysis, disregarding any curvature. Three or more measurements were taken in each examination to obtain the accurate mean measurement [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. The cartilage at the ends of the humerus were not included in the measurement. The body was measured between the epiphysis, which represents the portion of long bone formed by the primary ossification center. It appears as echogenic tubular structure in the arm, extending from the shoulder region to the elbow joint (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Ultrasound measurement of fetal humeral length).\u003c/p\u003e \u003cp\u003eThen the ultrasound was directed through the fetal pelvis to visualize the femur for measurement. Since the distal femur is usually flexed, the transducer was rotated from the position through 30\u0026ndash;45 degrees towards the abdomen until the full length of the femur was visualized (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Ultrasound measurement of fetal femoral length). The US beam was directed perpendicularly, along the long axis of the diaphysis of the bone and the diaphysis alone was measured after the hip and the knee were identified [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. The cartilage at the ends of the femur was not included in the measurement [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. The diaphysis was measured between the epiphysis, which represents the portion of the long bone formed by the primary ossification centers [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The femur appeared as a tubular echogenic structure in the thigh extending from the hip joint space to the knee joint (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Ultrasound measurement of fetal femoral length).\u003c/p\u003e \u003cp\u003eThe BPD was measured at the trans-thalamic plane with clear visualization of the thalami, the midline falx, and cavum septum pellucidum (CSP) as seen in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The thalami are diencephalic hypoechoic structures located on either side of the midline [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. The midline falx is seen as an echogenic line running antero-posteriorly in the midline bisecting the lateral ventricles while the CSP is seen anteriorly as an anechoic fluid filled space between the leaves of septum pellucidum. The calvaria appears as an oval echogenic structure which is smooth and symmetrical. BPD can be used for dating after 12 weeks. The BPD was measured from outer to inner edge of calvaria using calliper for tool (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Ultrasound measurement of fetal BPD\u003cb\u003e).\u003c/b\u003e\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe GA calculated from the LMP to the day of the ultrasound examination was taken as the known, control or standard menstrual age. Each parameter was compared with its standard chart and the accurate parameters noted for that known GA. (The standard GA was calculated by using the formula; The date of the ultrasound examination minus the date of the LMP)\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eFindings obtained from the obstetric patient\u0026rsquo;s sonographic examination reports were recorded in the data recording form. The generated data was entered into a computer database and the statistical package for social sciences (SPSS) version 22.0 software Chicago; Illinois USA was used for analysis. Descriptive statistics such as frequency, percentages, mean and standard deviation were used to summarize continuous variables. Pearson\u0026rsquo;s correlation was used to test relationships between continuous variables. Bland-Altman plot and paired t-test were used to identify any significant difference between measurements of GA by HL, FL and BPD. The results obtained were presented in tables, graphs and charts where necessary\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThis study was conducted on 413 pregnant women between 14 to 40 weeks of gestation, attending their booking and antenatal clinic in their 2nd and 3rd trimesters in National hospital Abuja from February to July 2023. They were clinically considered to be undergoing an uneventful pregnancy and certain of the date of their LMP. The GA was calculated from the LMP up to the day of examination with ultrasound, and this was taken as standard menstrual age. HL, FL and BPD and were taken.\u003c/p\u003e \u003cp\u003eThe age of participants ranged between 18 and 35 years, with majority falling between the ages of 30 and 35 years 206 (49.9%). Their mean and standard deviation was 29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6 years, the median was 29.0 years, and the 95% CI was 28.7\u0026ndash;29.4 years (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA large proportion of the pregnant women were multiparous accounting for 181 (43.8%) while grand multipara were the least with a total of 14 (3.4%) as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe gestational age of participants assessed by LMP and USS were similar, with mean and standard deviations of 29.4\u0026thinsp;\u0026plusmn;\u0026thinsp;7.6 and 29.5\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4 weeks respectively; and a median of 31 weeks each. Similarly, their 95% CIs were 28.7\u0026ndash;30.2 and 28.8\u0026ndash;30.2 weeks, respectively.\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows descriptive statistics for several ultrasound fetal biometry measurements taken from fetuses across different GA and it demonstrates that the mean and standard deviation for each of the measurements increases with GA. This implies the growth of the fetal humerus, head and femur with increasing GA over the course of pregnancy. The mean humeral length at 14 and 40 weeks was 15.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 mm and 66.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4 mm respectively and the mean femoral length at 14 and 40 weeks was 14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 mm and 75.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 mm respectively. It was observed that the mean humeral length increased gradually with increasing age from 15.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5 mm at 14 weeks to 66.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4 mm at 40 weeks. It was also observed that the femoral length gradually increased with an increase in GA from 14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4 mm at 14 weeks to 75.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5 mm at 40 weeks. The mean BPD at 14 weeks and 40 weeks was 27.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4 mm and 97.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9 mm respectively\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMean value of fetal HL, FL and BPD from 14 to 40 weeks of gestation\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGA (Weeks)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eFrequency (%)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eHL\u003c/p\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFL\u003c/p\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eBPD\u003c/p\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5(1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e15.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e14.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e27.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7(1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e18.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e18.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e30.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7(1.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e20.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e21.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e34.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5(1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e23.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e37.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17(4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e25.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e26.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e40.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13(3.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e30.2\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e46.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17(4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e34.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e48.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11(2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e32.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e34.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e50.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8(1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e35.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e38.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e53.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e6(1.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e39.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e41.8\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e58.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8(1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e41.8\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e45.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e62.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e22(5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e43.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e45.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e61.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e28(6.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e43.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e47.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e64.5\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8(1.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e48.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e51.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e71.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e11(2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e48.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e54.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e74.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13(3.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e49.7\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e54.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e72.8\u0026thinsp;\u0026plusmn;\u0026thinsp;3.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e13(3.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e51.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e58.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e75.5\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14(3.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e55.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e62.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e23(5.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e56.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e62.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e81.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14(3.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e57.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e63.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e84.3\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e14(3.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e59.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e67.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e86.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e17(4.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e60.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e67.7\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e87.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e18(4.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e63.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e71.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e91.5\u0026thinsp;\u0026plusmn;\u0026thinsp;9.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e41(9.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e64.6\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e72.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e92.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e45(10.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e65.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e74.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e93.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e16(3.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e66.2\u0026thinsp;\u0026plusmn;\u0026thinsp;1.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e74.9\u0026thinsp;\u0026plusmn;\u0026thinsp;1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e94.1\u0026thinsp;\u0026plusmn;\u0026thinsp;2.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e12(2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e66.3\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c4\"\u003e \u003cp\u003e75.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c5\"\u003e \u003cp\u003e97.1\u0026thinsp;\u0026plusmn;\u0026thinsp;1.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eHL= Humeral length\u003c/p\u003e \u003cp\u003eFL= Femoral Length\u003c/p\u003e \u003cp\u003eBPD\u0026thinsp;=\u0026thinsp;Biparietal diameter\u003c/p\u003e \u003cp\u003eSD\u0026thinsp;=\u0026thinsp;Standard deviation\u003c/p\u003e \u003cp\u003eGA\u0026thinsp;=\u0026thinsp;Gestational age\u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e shows a scatter plot of humeral length (mm) versus gestational age (weeks). The data points are generally clustered along a positive trend line, indicating that there is a positive correlation between humeral length and gestational age with a coefficient of 0.988. This is statistically significant with a p-value of \u0026lt;\u0026thinsp;0.001. The regression line is described by the equation USS\u0026thinsp;=\u0026thinsp;0.4917HL\u0026thinsp;+\u0026thinsp;4.9487\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e shows a positive linear correlation between the two variables, implying that as GA increases, The FL also increases. The plot shows a high degree of correlation with a coefficient of 0.990, meaning that the relationship between the two variable is strong. It is statistically significant with a p-value of \u0026lt;\u0026thinsp;0.001. The regression line is described by the equation USS\u0026thinsp;=\u0026thinsp;0.414FL\u0026thinsp;+\u0026thinsp;6.6023\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e shows a positive linear correlation between the two variables, implying that as GA increases, the BPD also increases. The plot shows a high degree of correlation with a coefficient of 0.983, meaning that the relationship between the two variable is strong. It is statistically significant with a p-value of \u0026lt;\u0026thinsp;0.001. The regression line is described by the equation USS\u0026thinsp;=\u0026thinsp;0.367BPD\u0026thinsp;+\u0026thinsp;2.778\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents the results of a multiple linear regression analysis with various fetal biometric measurements as predictors of gestational age. The coefficients represent the estimated change in gestational age for a one-unit increase in each predictor, holding all other variables constant. The standard error (SE) indicates the precision of the coefficient estimates, while the t-statistic and p-value assess the significance of each predictor. The results show that FL, BPD, and HL are all significantly associated with gestational age, as indicated by their t-statistics and p-values.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultiple Linear Regression Showing the Relationship Between Predictor Variables and Gestational Age by USS\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePredictors\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCoefficient\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStandard Error\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003et-statistics\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eP-value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eConstant\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5.185\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.226\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e22.912\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHL (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.090\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.030\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.946\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.003*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFL (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.240\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e9.598\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBPD (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.090\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e6.576\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003e*Significant at 95%\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigures \u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e9\u003c/span\u003e and \u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e show Bland-Altman plots assessing the agreement between humeral length gestational age (HLGA) and femoral length gestational age (FLGA) on one hand, and biparietal diameter gestational age (BPDGA) on the other. There was no significant bias between HLGA and FLGA, with a mean difference of 0.042 and limits of agreement of -2.6589 and 2.7843 indicating that humeral length is a reliable measure for estimating gestational age.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThere was also no significant bias between the humeral length gestational age (HLGA) and biparietal diameter gestational age (BPDGA), with a mean difference of -0.0654 and limits of agreement of -2.5068 and 2.3759 indicating that humeral length is a reliable measure for estimating gestational age (Fig.\u0026nbsp;\u003cspan refid=\"Fig10\" class=\"InternalRef\"\u003e10\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure \u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e11\u003c/span\u003e is a correlation matrix revealing a strong positive relationship among the fetal biophysical parameters: Humeral Length Gestational Age (HLGA), Femur Length Gestational Age (FLGA) and Biparietal Diameter Gestational Age (BPDGA). All correlation coefficients are equal to or greater than 0.98, indicating that the gestational age estimates derived from these parameters are highly consistent and reliable in assessing fetal growth. The strongest correlations are observed between BPDGA and HLGA (r\u0026thinsp;=\u0026thinsp;0.986).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eWomen are fertile between menarche and menopause, but the peak reproductive ages are from 18\u0026ndash;29 years [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. A recent trend however shows that the predominant biological reproductive span of women ranges from 30.9\u0026ndash;39.3 years [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. In keeping with this trend, the majority (49.9%) of the participants in our study were in the 30\u0026ndash;35 years age range. The majority of participants in our study (47.2%) were multiparous, consistent with the findings of 40% reported by Maharaj et al. in Fiji but lower than the 67.9% reported by Saliu et al. in Kano, Nigeria [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The reasons for this same-country variation are unclear but could be attributed to heterogeneity of population in Abuja, the location of the index study, which being more cosmopolitan has more variety in educational status, cultural norms and beliefs, and more awareness of and greater access to modern contraceptive methods which influence family size. The mean maternal age in the index study of 29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6 years similar to 29\u0026thinsp;\u0026plusmn;\u0026thinsp;6 years reported by Saliu et al. in Kano, Nigeria; 28.3 years by Yazdani et al in Sweden; and 28.7 years by Benzies et al in the Netherlands [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. This trend of increased age of onset of biological reproductive span and prevalence of multiparity among women of advanced maternal age reflects a shift in reproductive behavior, with women choosing to have children later in life but often completing their families within a shorter time frame [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFirst trimester ultrasound measurement of CRL remain the standard, most accurate method for estimating fetal age, however second and third trimester ultrasound measurements of BPD, HC, AC, and FL are also methods [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. In the current study, ultrasound measurements of fetal HL, FL and BPD, all demonstrated an expected linear relationship with advancing gestational age between 14\u0026ndash;40 weeks. The observed means and standard deviations for each parameter align closely with fetal growth trajectories documented in previous literature [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. HL measurements are not routinely used in fetal GA estimation, however in this study linear regression modelling allowed the development of a population specific formula for predicting GA based on sonographic measurement of fetal HL. The regression coefficient of 0.4917 and constant intercept of 4.949 weeks obtained in our study aligns with the regression coefficient of 0.5213 and constant intercept of 4.905 weeks reported by Mital et al in India [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. It provides external validation of the linear relationship between advancing gestational age and longitudinal humeral growth. Overall, the excellent agreement in HL regression slopes affirms that humeral length is a strong and reliable predictor of gestational age across populations.\u003c/p\u003e \u003cp\u003eScatterplots with fitted regression lines and regression equations were created to observe the relationships between gestational age by USS and HL, FL and BPD respectively. HL, FL and BPD regression lines were positively related to the GA, in keeping with similar studies by Mounika et al., Aggarwal et al., and Adiri et al. who observed similar associations while the regression equations were different [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The disparity in regression equations may be due to variations caused by several factors such as race, socioeconomic status, genetics, geographical location, and associated maternal diseases [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Multiple linear regression analysis was also performed, which revealed HL, FL and BPD were all statistically significant predictors of GA.\u003c/p\u003e \u003cp\u003eBland-Altman plots were created to compare the gestational age derived from HL and that derived from FL and BPD. All the Bland-Altman plots showed that most of the points were within the limits of agreement, indicating that HL is a reliable measure for estimating GA. This finding is similar to those from studies carried out by Patre et al., Mital et al., Gamerradin et al., and Hassan [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Despite these positive correlations with the more commonly used fetal biometric parameters, HL is not as widely used or recognized as a primary biometric parameter for estimating gestational age. This may be because the routinely used fetal biometry parameters are usually reliable. In conditions where their reliability fails or reduces, HL can serve as an additional parameter to increase accuracy. Nevertheless, it is often recommended to use multiple biometric parameters together for more accurate estimations [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Variability in fetal growth patterns, the influence of factors such as ethnicity and maternal health can also affect the accuracy of humeral length limiting its utility as a standalone measure [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThe major limitation of this study was that it was hospital-based and, therefore, analyzed only the parameters of participants who accessed antenatal care at our center. Accordingly, the findings may not be wholly representative of the general population. Another limitation was that the data was collected at a single time point rather than following fetuses longitudinally across gestation. This limits characterization of individualized growth trajectories. Finally, the restriction of age range of participants to 18\u0026ndash;35 years meant that our findings may not accurately assess women outside that age bracket.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis study shows that ultrasonographic measurement of fetal HL provides a reliable and accurate estimate of GA in singleton pregnancies comparable to measurements of FL and BPD. The maternal age of participants did not affect the reliability of these measurements. Furthermore, the strong linear association between increasing gestational age and increasing HL reflects the normal pattern of longitudinal bone development in the uterus. When in doubt of the accuracy of routine parameters especially in cases of hydrocephalus, anencephaly, multiple gestation, and term pregnancy with engaged head or breech positions, HL should be employed as an alternative and reliable option.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eIUGR\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eIntrauterine Growth Restriction\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eLMP\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eLast Menstrual Period\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eMHz\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMega Hertz\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eUS\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUltrasound\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eCI\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eConfidence interval\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eEDD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eExpected Delivery Date\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eCRL\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCrown rump length\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eGSD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGestational sac diameter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eGA\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGestational Age\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eAC\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eAbdominal circumference\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eBPD\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eBiparietal diameter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eFL\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eFemur Length\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eHC\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHead circumference\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eHL\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHumeral Length\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eFLGA\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUltrasound gestational age by Femur length\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eHLGA\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUltrasound gestational age by Humeral length\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eBPDGA\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eUltrasound gestational age by Biparietal diameter\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u003cb\u003eHREC\u003c/b\u003e\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eHealth Research Ethics Committee\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eEthical approval was duly obtained from Health Research Ethics Committee (HREC) of National Hospital Abuja via NHA/ADMIN/236/V.VII/. Informed consent was obtained from participants.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author (Oluchi Germaine Umenzekwe) on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding to report\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eContributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOGU is the principal and corresponding author. KNE put forward important revision suggestions and made corresponding modifications for this article. All authors contributed to the article and approved the submitted version.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors give thanks to all participants who volunteered to participate in this study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLee LH, Bradburn E, Craik R, Yaqub M, Norris SA, Ismail LC, et al. Machine learning for accurate estimation of fetal gestational age based on ultrasound images. NPJ Digit Med. 2023;6:36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBasilico R, Pizzi AD, Mincuzzi E, Danzi R, Ricciardulli A, Grzycka-Kowalczyk L. Non-traumatic Abdominal and Pelvic Emergencies in Pregnant Patients: Role of Ultrasound. In: Patlas MN, Katz DS, Scaglione M, editors. Emergency Imaging of Pregnant Patients [Internet]. Cham: Springer International Publishing; 2020. pp. 63\u0026ndash;85. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-3-030-42722-1_4\u003c/span\u003e\u003cspan address=\"10.1007/978-3-030-42722-1_4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e, Accessed 4 Feb 2024.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNaidu K, Fredlund KL. Gestational Age Assessment. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.ncbi.nlm.nih.gov/books/NBK526000/\u003c/span\u003e\u003cspan address=\"http://www.ncbi.nlm.nih.gov/books/NBK526000/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 4 Feb 2024.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKalish RB, Chervenak FA. Sonographic determination of gestational age. Ultrasound Rev Obstet Gynecol. 2005;5(4):254\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eButt K, Lim KI. Guideline 388-Determination of Gestational Age by Ultrasound. J Obstet Gynaecol Can. 2019;41(10):1497\u0026ndash;507.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSalomon Lj, Alfirevic Z, Da Silva Costa F, Deter Rl, Figueras F, Ghi T, et al. ISUOG Practice Guidelines: ultrasound assessment of fetal biometry and growth. Ultrasound Obstet Gynecol. 2019;53(6):715\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCampbell S. An improved method of fetal cephalometry by ultrasound. J Obstet Gynaecol Br Commonw. 1968;75(5):568\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCampbell S. The prediction of fetal maturity by ultrasonic measurement of the biparietal diameter. J Obstet Gynaecol Br Commonw. 1969;76(7):603\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIzadifar Z, Izadifar Z, Chapman D, Babyn P. An Introduction to High Intensity Focused Ultrasound: Systematic Review on Principles, Devices, and Clinical Applications. J Clin Med. 2020;9(2):460.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarg A, Habeebullah S, Rathod S. Comparison of Ultrasonic Measurement of Fetal Kidney Length with Other Fetal Biometric Indices in Determining Gestational Age in Third Trimester in South Indian Population. J South Asian Feder Obst Gynae. 2022;14(5):587\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eŽaliūnas B, Bartkevičienė D, Drąsutienė G, Utkus A, Kurmanavičius J. Fetal biometry: Relevance in obstetrical practice. Medicina. 2017;53(6):357\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRao BRC, Sreepadma S, Associate, Professor, Department of Anatomy, SDM College of Medical SciencesHospital, Dharwad, Karnataka, India., Kalghatgi RN. The Study of Relation Between Gestational Age of Human Fetuses and the Diaphyseal Length of Femur usin Ultrasonography. IJAR. 2017;5(1.1):3342\u0026ndash;3349.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLees CC, Stampalija T, Baschat AA, Da Silva Costa F, Ferrazzi E, Figueras F, et al. ISUOG Practice Guidelines: diagnosis and management of small-for‐gestational‐age FETUS and fetal growth restriction. Ultrasound Obstet Gyne. 2020;56(2):298312.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlzubaidi M, Agus M, Alyafei K, Althelaya KA, Shah U, Abd-Alrazaq A, et al. Toward deep observation: A systematic survey on artificial intelligence techniques to monitor FETUS via ultrasound images. iScience. 2022;25(8):104713.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeter RL, Lee W, Yeo L, Erez O, Ramamurthy U, Naik M, et al. Individualized growth assessment: conceptual framework and practical implementation for the evaluation of fetal growth and neonatal growth outcome. Am J Obstet Gynecol. 2018;218(Suppl 2):656\u0026ndash;78.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eProcas-Ramon B, Hierro-Espinosa C, Salim I, Impey L, Ioannou C. The impact of individual sonographer variation on the detection of small for gestational age Fetuses using a third trimester growth scan. J Clin Ultrasound. 2021;49(5):442\u0026ndash;50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eThalamus [Internet]. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.fetalultrasound.com/online/text/100-089.HTM\u003c/span\u003e\u003cspan address=\"http://www.fetalultrasound.com/online/text/100-089.HTM\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 23 Sep 2023.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaving. April a baby after age 35 \u0026ndash; how aging affects fertility and pregnancy [Internet]. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy#\u003c/span\u003e\u003cspan address=\"https://www.acog.org/womens-health/faqs/having-a-baby-after-age-35-how-aging-affects-fertility-and-pregnancy#\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 1 2026.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNabhan AF, Mburu G, Elshafeey F, Magdi R, Kamel M, Elshebiny M, Abuelnaga YG, Ghonim M, Abdelhamid MH, Ghonim M, Eid P, Morsy A, Nasser M, Abdelwahab N, Elhayatmy F, Hussein AA, Elgabaly N, Sawires E, Tarkhan Y, Doas Y, Farrag N, Amir A, Gobran MF, Maged M, Abdulhady M, Sherif Y, Dyab M, Kiarie J. Women's reproductive span: a systematic scoping review. Hum Reprod Open. 2022;2hoac005. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/hropen/hoac005\u003c/span\u003e\u003cspan address=\"10.1093/hropen/hoac005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaharaj R, Mohammadnezhad M. Perception of pregnant women towards early antenatal visit in Fiji: a qualitative study. BMC Pregnancy Childbirth. 2022;22(1):111.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaliu MA, Salihu A, Mada SB, Owolabi OA. Dyslipidaemia-related cardiovascular risk among pregnant women attending Aminu Kano Teaching Hospital Kano: A longitudinal study. J Taibah Univ Med Sci. 2021;16(6):870\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYazdani M, Amirshahi E, Shakeri A, Amirshahi R, Malekmakan L. Prenatal and Maternal Outcomes in Advanced Maternal Age, a Comparative Study. Women\u0026rsquo;s Health Bull. 2015;2(2):1\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenzies KM. Advanced maternal age: Are decisions about the timing of child-bearing a failure to understand the risks? CMAJ. 2008;178(2):183\u0026ndash;4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKunarathnam V, Tafti D. Sonography Assessment of Gestational Age. [Updated 2026 Feb 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan-. Available from: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.ncbi.nlm.nih.gov/books/NBK570610/\u003c/span\u003e\u003cspan address=\"https://www.ncbi.nlm.nih.gov/books/NBK570610/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 1 April 2026.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKumar S, Pandey VD, Yogesh Y. Fetal humerus Length for Prediction of Gestational Age: An Ultrasonographic Study. JMSCR. 2018;6(12):171\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePatre V, Aryan AK, Sahu P, Patre V. Ultrasonographic Evaluation of Fetal Humerus Length for Assessment of Gestational Age and Its Comparison with Other Conventional Parameters. Int J Sci Stud. 2015;3(7):58\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMital P, Ainani R, Hooja N, Sonkhya P, Pradodh V, Chaudhary K, et al. A cross-sectional study to evaluate sonographic fetal humerus length for estimation of gestational age in normal singleton pregnancies at a tertiary care centre. Int J Reprod Contracept Obstet Gynecol. 2019;8(9):3622\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHammed MV, Mallikarjunappa A, Revathi RB, Parimal M. Ultrasonographic Evaluation Of Fetal Humerus Length For Assessment Of Gestational Age And Its Comparison With Other Conventional Parameters. Int J Sci Res. 2019;8(12):9\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAggarwal N, Sharma GL. Fetal ultrasound parameters: Reference values for a local perspective. Indian J Radiol Imaging. 2020;30(2):149\u0026ndash;55.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdiri CO, Anyanwu GE, Agwuna KK, Obikili EN, Ezugworie OJ, Agu AU, et al. Use of fetal biometry in the assessment of gestational age in South East Nigeria: Femur length and biparietal diameter. Niger J Clin Pract. 2015;18(4):477\u0026ndash;82.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGameraddin M, Abdelmaboud S, Alshoabi S. The role of fetal humeral length in determination of gestational age compared with femoral length using ultrasonography. IOSR-JDMS. 2015;14(5):65\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHassan MG. Humeral Length versus Femur Length for Estimating Fetal Age in the Third Trimester Using Ultrasound among Saudi fetuses. J Med Ultrasound. 2022;31(2):133\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"humeral length, femoral length, biparietal diameter, gestational age, ultrasound","lastPublishedDoi":"10.21203/rs.3.rs-9305071/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9305071/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eThis study aims to evaluate the reliability of sonographic humeral length (HL) as a predictor of gestational age (GA), comparing its effectiveness to standard measurements like femur length (FL) and biparietal diameter (BPD). While the latter are routinely used, individual growth variations can cause discrepancies in measurements. The research explores if HL can help address these inconsistencies and offer a more comprehensive evaluation of fetal development.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis was a descriptive cross-sectional study that involved normal pregnant women with known first day of the last menstrual period (LMP), carrying normal singleton fetus in their second and third trimesters (14\u0026ndash;40 weeks of GA). Grey scale ultrasound was used to measure the HL, FL and BPD to estimate the sonographic GA. Generated data was entered into a computer database and the statistical package for social sciences (SPSS) version 22.0 software Chicago, Illinois USA was used for analysis. Descriptive statistics were used to summarize continuous variables; Pearson\u0026rsquo;s correlation was used to test for relationships between continuous variables. Bland-Altman plot and paired t-test were used to identify any significant difference between measurements of GA by HL, FL and BPD\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThis study involved 413 pregnant women in their 2nd and 3rd trimesters. Linear regression modelling was used to develop a formula for predicting gestational age with HL, predicted GA\u0026thinsp;=\u0026thinsp;0.4917HL\u0026thinsp;+\u0026thinsp;4.9487. Scatterplots with fitted regression lines showed a positive correlation between all measured fetal biometric parameters (HL and FL, BPD) and GA. A Bland-Altman plot was used to demonstrate the excellent agreement between HL and other routinely used parameters like FL and BPD.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eThis study demonstrated that fetal humeral length measurements were accurate alternatives to the conventional fetal biometric parameters such as FL and BPD. This can be applicable to certain conditions such as skeletal dysplasias, down syndrome, congenital anomalies, multiple gestation, engaged fetal head at term, breech positions and also when the growth of the femur may deviate due to environmental or genetic factors.\u003c/p\u003e","manuscriptTitle":"Utility of Fetal Humeral Length Measurements in Gestational Age Estimation in the Second and Third Trimesters in Pregnant Women Attending Antenatal Care Clinics in a Nigerian Tertiary Hospital: A Descriptive Cross-sectional Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-18 16:44:11","doi":"10.21203/rs.3.rs-9305071/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"22035828656913979199059541429192093386","date":"2026-05-20T16:39:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-19T14:19:58+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"157984413755088104801174220738191574010","date":"2026-05-09T09:12:00+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-05-08T10:15:03+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-04-16T11:16:21+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-04-13T12:54:40+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-04-08T16:25:02+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Pregnancy and Childbirth","date":"2026-04-08T15:57:25+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-pregnancy-and-childbirth","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"prch","sideBox":"Learn more about [BMC Pregnancy and Childbirth](http://bmcpregnancychildbirth.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/prch/default.aspx","title":"BMC Pregnancy and Childbirth","twitterHandle":"@BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"91ab8fcb-b9ce-4cb2-a982-7aa2dc69165c","owner":[],"postedDate":"May 18th, 2026","published":true,"recentEditorialEvents":[{"type":"reviewerAgreed","content":"22035828656913979199059541429192093386","date":"2026-05-20T16:39:53+00:00","index":64,"fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-19T14:19:58+00:00","index":63,"fulltext":""},{"type":"reviewerAgreed","content":"157984413755088104801174220738191574010","date":"2026-05-09T09:12:00+00:00","index":40,"fulltext":""},{"type":"reviewersInvited","content":"30","date":"2026-05-08T10:15:03+00:00","index":"","fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T16:44:12+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-18 16:44:11","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9305071","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9305071","identity":"rs-9305071","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}