In vitro fertilization in a lower-middle-income country: success rates of frozen versus fresh embryo transfer-A retrospective cohort study

In vitro fertilization in a lower-middle-income country: success rates of frozen versus fresh embryo transfer-A retrospective cohort 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 In vitro fertilization in a lower-middle-income country: success rates of frozen versus fresh embryo transfer-A retrospective cohort study Ayalew Marye, Mekitie Wondafrash, Abraham Fessehaye Sium This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9600436/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background : Infertility is a global health concern, often requiring in vitro fertilization (IVF). A key decision in IVF is choosing between fresh embryo transfer (ET) and frozen embryo transfer (FET). Advances in cryopreservation have shifted preference towards FET, yet debates about its comparative effectiveness persist. This study compares the success rates of IVF following fresh versus frozen ET at a Center for Fertility and reproductive medicine in Sub-Saharan Africa setting. Methods : This was a retrospective cohort study conducted at St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia. Data from women undergoing fresh and frozen ET between January 1 and December 31, 2023, were analyzed. Variables included sociodemographic factors, infertility causes, treatment protocols, and pregnancy outcomes. The primary outcomes measured were biochemical pregnancy rates, clinical pregnancy rates, and live birth rates. Results : A total of 292 women were included, with 149 undergoing fresh ET and 143 undergoing frozen ET. The mean age of women in fresh cycles was 32.6 years, compared to 31.7 years in frozen cycles. Female factor infertility was the most common cause in both groups, with higher prevalence in the frozen group (55.9% vs. 45.6%, p = 0.013). FET cycles showed better outcomes, with 74.1% of embryos graded as "best" compared to 61.1% in fresh cycles (p = 0.014). FET also required less gonadotropin (2558.2 IU vs. 3030.7 IU, p = 0.024) and yielded more mature follicles and oocytes (p < 0.001). Positive biochemical pregnancy rates were higher in the frozen group (61.3%, p < 0.001). Conclusions : FET is associated with higher pregnancy rates, improved embryo quality, and reduced gonadotropin requirements compared to fresh ET. These findings support FET as a preferred approach in IVF, particularly for high responders and those at risk of ovarian hyperstimulation syndrome. Further research is needed on its long-term outcomes. Obstetrics & Gynecology In vitro fertilization Frozen embryo transfer Fresh embryo transfer Pregnancy outcomes Introduction Infertility represents a significant global health challenge, affecting millions of couples worldwide and often necessitating the use of advanced assisted reproductive technologies (ART) such as in vitro fertilization (IVF)[1]. A critical decision in IVF treatment is the choice between fresh embryo transfer (ET) and frozen embryo transfer (FET). Historically, fresh ET was the predominant approach, characterized by the immediate transfer of embryos into the uterus following fertilization [2]. However, advances in cryopreservation techniques, including vitrification, have shifted the landscape toward FET, enabling the freezing and storage of embryos for later use [3]. This evolution has sparked ongoing debates regarding these two approaches' comparative efficacy and safety, with varying implications for clinical outcomes. Numerous factors influence the success rates of fresh and frozen embryo transfers, such as embryo quality, endometrial receptivity, and patient-specific characteristics, including age and underlying infertility conditions like polycystic ovary syndrome (PCOS). FET is often associated with reduced risks of ovarian hyperstimulation syndrome (OHSS), improved synchronization of the endometrial environment, and higher clinical pregnancy rates (CPR) in certain populations, such as high responders and those undergoing preimplantation genetic testing (PGT) [4,5]. Conversely, advocates for fresh ET emphasize its potential advantages, including a natural alignment between the embryo’s developmental stage and the uterine environment, which may enhance implantation success in specific cases [6,7]. Moreover, fresh ET retains some advantages, including shorter treatment cycles and avoiding freezing-thawing processes, which might compromise embryo viability [8,9]. The ongoing debate over the optimal embryo transfer strategy is reflected in conflicting results from various studies. While randomized controlled trials and meta-analyses have demonstrated higher pregnancy and live birth rates with FET [10,11], other research highlights comparable or superior outcomes with fresh ET in specific populations, such as intermediate and low responders [6,12]. Despite extensive research, gaps remain in understanding the nuanced dynamics of fresh versus frozen embryo transfers, particularly in low-resource settings such as Ethiopia. Despite FET's growing popularity in high-income countries, its application in resource-limited environments remains underexplored[13,14], leaving questions about the applicability of findings in different socioeconomic and healthcare contexts. Factors such as patient demographics, resource availability, and clinical expertise may influence outcomes, underscoring the need for region-specific studies to inform practice and policy [4,15]. In addition to clinical outcomes such as pregnancy rates and live birth rates (LBR), the choice of embryo transfer method may also impact complications like OHSS and multiple pregnancies. Exploring these factors in diverse settings can contribute to optimizing ART protocols, improving patient care, and providing evidence-based recommendations for healthcare providers [16]. This study aimed at comparting success rates of IVF treatments following fresh versus frozen embryo transfers. Materials and Methods Study setting and period: The study was conducted at Center for Reproductive Medicine (CFRM), the only government-owned center established in 2018 under St. Paul’s Hospital Millennium Medical College (SPHMMC), which provides comprehensive reproductive medicine and fertility care services to clients from Ethiopia and abroad. The center offers services including minimally invasive surgery, assisted reproductive techniques such as in vitro fertilization (IVF) and intrauterine insemination (IUI), as well as diagnostic workup and counseling for reproductive endocrinology and anomalies. On average, the center handles 1,000 IVF cycles annually. We collected data of patients who underwent embryo transfers between January 1, 2023, and December 31, 2023. To ensure data clarity, cases within three months of the data collection date were excluded, particularly for pregnancies at risk of subsequent complications. Study designs This study was an institution-based retrospective cohort study conducted at the CFRM of SPHMMC in Addis Ababa, Ethiopia. Study population: The source population included all women who underwent fresh embryo transfer (ET) or frozen embryo transfer (FET) at CFRM during the study period. The study population comprised women who met specific inclusion and exclusion criteria. Inclusion and exclusion criteria: The inclusion criteria included women who underwent embryo transfer (fresh or frozen) between January 1, 2023, and December 31, 2023, with charts containing complete and clear documentation. Exclusion criteria encompassed women who did not proceed with embryo transfer after oocyte pick-up (OPU), those with an endometrial thickness outside the range of 7–14 mm, cases involving difficult embryo transfers, and women who discontinued luteal phase support (LPS) medications. Sample size calculation : The sample size was calculated using the double population proportion formula for cohort studies. A study conducted in Iran in 2023 comparing fresh and frozen embryo transfers provided the basis for the calculation [2]: n = (Z α/2 +Z β ) 2 x (p1(1-p 1 ) + p 2 (1-p 2 )) / (p 1 -p 2 ) 2 where Z α/2 is the critical value of the Normal distribution at α/2 (for a confidence level of 95%, α is 0.05 and the critical value is 1.96), Z β is the critical value of the Normal distribution at β (for a power of 80%, β is 0.2 and the critical value is 0.84) and p 1 = 54.3% and p 2 =70.8 are the expected sample proportions of the two groups. The calculated sample size was 296 participants, with 148 women in each group (fresh ET and frozen ET). Study variables: The study examines various dependent and independent variables. The dependent variables assessed are biochemical pregnancy, clinical pregnancy, the number of gestations, and the incidence of ovarian hyperstimulation syndrome (OHSS). The independent variables include sociodemographic factors, endometrial thickness, antral follicular count, the day of the embryo during transfer, the duration of freezing before embryo thawing, the clinician's level of expertise during the embryo transfer, the number of oocytes collected and fertilized, and the number of embryos transferred. Data collection and procedures : Two trained research assistants abstracted data from patient records using a pretested structured data abstraction tool. When necessary, patients were contacted via the phone numbers provided in their charts to clarify incomplete or unclear information. Data were collected using KoboToolbox, and abstraction accuracy was monitored daily. Data analysis Data analysis was performed using Stata 17 statistical software. Descriptive statistics, including percentages, means with standard deviations (SD), and medians with interquartile ranges (IQR), were calculated. Associations between independent and dependent variables were assessed using chi-square tests for categorical outcomes. For continuous outcomes, parametric (t-tests) and non-parametric (Mann-Whitney U tests) methods were employed, depending on data normality. Statistical significance was set at a p-value of <0.05, and results were presented in tables and graphs. Ethical considerations: Ethical clearance was obtained from the Institutional Review Board (IRB) of SPHMMC. All information about the patients and their husbands was kept confidential, and no personal information was shared with third parties. Any needs for counseling, treatment, or appointments were addressed by phone. Information extracted from the medical charts was solely for data abstraction to answer the research question. The data collection process and other aspects of the study did not interfere with the women's or their husbands' treatment or follow-up. The researcher had no conflicts of interest with any individuals, groups, or pharmaceutical companies. Results The study, which included 292 women undergoing fresh (n=149, 51%) and frozen (n=143, 49%) embryo transfers (ET), revealed several notable differences between the two groups. The mean age of women undergoing fresh cycles was 32.6 years (SD 4.86), slightly older than those in frozen cycles (31.7 years). A higher proportion of women aged ≥35 years end up in fresh ET (45% vs. 31.5%, p = 0.022), suggesting that older women were more likely to have fresh cycles. (Table 1). Primary infertility was more common in frozen cycles (81.8%) compared to fresh cycles (69.1%, p = 0.014). Additionally, the majority of women in the fresh group (98.7%) and frozen group (86%) had no previous live births, with a statistically significant difference favoring the frozen group (p < 0.001). Female factor infertility was the leading cause of infertility in both groups but was more prevalent in the frozen group (55.9% vs. 45.6%, p = 0.013). Unexplained infertility was the second most common cause in frozen cycles (25.9%), while male factor infertility was more frequent in fresh cycles (26.8% vs. 16.1%). Testicular Sperm Extraction (TESE) was a common sperm retrieval method for male factor infertility cases, used in 87.5% of fresh cycles and 78.3% of frozen cycles (Table 1). The antagonist protocol was the predominant ovarian stimulation method in both groups (94% vs. 87.4%, p = 0.044), with higher usage in fresh cycles (Table 1). The type of fertilization method varied slightly between groups, with Intracytoplasmic Sperm Injection (ICSI) being more common in fresh cycles (69.1% vs. 62.2%), while conventional IVF was more frequently used in frozen cycles (37.8% vs. 30.9%, p = 0.21; Table 1). Regarding embryo quality, a higher proportion of best-grade embryos was observed in frozen cycles (74.1% vs. 61.1%, p = 0.014; Table 1). Women in fresh cycles required a significantly higher total gonadotropin dose (median 3030.7 IU vs. 2558.2 IU, p = 0.026) and had fewer mature follicles on the day of the trigger (median 5 vs. 13, p < 0.001). Similarly, the total number of oocytes retrieved was significantly lower in fresh cycles (median 6 vs. 16, p < 0.001), as was the number of mature (M2) oocytes (median 4 vs. 10, p < 0.001). In addition, the number of blastocysts on day five was markedly higher in frozen cycles (median 4 vs. 0, p < 0.001; Table 3). The endometrial thickness on the day of the trigger was also slightly greater in frozen cycles (median 10 mm vs. 9 mm, p = 0.002) (Table 3). Biochemical pregnancy outcomes revealed significant differences between the groups, with 61.3% of positive pregnancies occurring in frozen cycles compared to 38.7% in fresh cycles. Conversely, 64.1% of negative biochemical pregnancies were observed in fresh cycles compared to 35.9% in frozen cycles (p < 0.001; Table 2). Age significantly influenced pregnancy outcomes, as younger women (<35 years) had a higher proportion of positive biochemical pregnancies (67.3%, p = 0.042; Table 4). Among women with positive pregnancies, 88.7% had no prior live births, compared to 96.5% in those with negative outcomes (p =0.014; Table 4). Among women with positive biochemical pregnancies and after ultrasound examination at the eighth week, 127 (84.7%) had active fetuses on ultrasound, distributed as 91 singletons, 34 twins, and 2 triplets, while 12 (8%) had an empty uterus, and 11 (7.3%) had an anembryonic pregnancy (data not shown). Vaginal bleeding up to 10 weeks after embryo transfer was reported in 10 women (6.7%), whereas the majority (93.3%) did not experience bleeding. Frozen embryo transfers were performed for various reasons, including leftover embryos from previous transfers (55%), suboptimal endometrial quality (15%), and prevention of Ovarian Hyperstimulation Syndrome (OHSS; 20%; Table 4). Discussion The main objective of this study was to compare the outcomes of fresh embryo transfer (ET) with that of frozen embryo transfer (FET) in vitro fertilization (IVF) in a low-middle income setting. We found superior clinical outcomes, including higher biochemical pregnancy rates and reduced risks of ovarian hyperstimulation syndrome (OHSS), in women who had IVF with frozen embryo transfer compared to those who had the same procedure with fresh embryo transfer. Although existing evidence shows that frozen embryo transfer has more IVF success rate compared to Fresh embryo transfer [4,17], there is limited evidence on this topic from low-middle income countries such as the Sub-Saharan Africa region where infertility is more prevalent than any part of the world with IVF care services absents in most countries, especially at a public institution [18]. In the present study, compared to fresh embryo transfer, FET consistently showed higher success rates across all age groups, particularly among younger women, who experienced significantly higher positive biochemical pregnancy rates compared to their counterparts in fresh ET cycles. Among the interesting findings of this study, FET cycles required significantly lower gonadotropin dosages, produced more mature follicles, and yielded higher numbers of retrieved and fertilized oocytes, reinforcing the notion that FET protocols are less physically demanding and potentially more cost-effective in the long term [19]. The reduced rates of negative biochemical pregnancies and significantly higher rates of positive outcomes in FET also underscore its clinical advantages, particularly for high responders at risk of OHSS. Close to 9 in 10 women who had positive biochemical pregnancies in this study had no prior live births, highlighting the potential of FET to support first-time mothers in achieving successful pregnancies. Furthermore, the data on early pregnancy outcomes showed that 84.7% of pregnancies in this study had active fetuses on ultrasound, distributed as 91 singletons, 34 twins, and 2 triplets, while 93.3% of women reported no vaginal bleeding during early gestation. These findings provide additional support for the clinical effectiveness of FET in achieving favorable pregnancy outcomes. Strengths of this study include being among the first to present on Frozen embryo transfer from low-middle income countries and proper sample size allocation. Incomplete documentation in some cases and the inability to account for inter-practitioner differences among clinicians and embryologists may have influenced the outcomes are the main limitations of this study. Future research should address these limitations and explore long-term maternal and neonatal outcomes associated with fresh and frozen ET protocols. Conclusion Our study supports the growing preference for FET in IVF treatments, demonstrating its superior clinical outcomes in low-middle income country, particularly in terms of CPR and reduced OHSS risks. While fresh ET remains a viable option in specific clinical scenarios, individualized treatment planning based on patient characteristics and clinical history is essential. Further large-scale, multicenter randomized controlled trials are warranted to validate these findings and refine ART protocols, especially in resource-constrained settings like Ethiopia. Declarations Author contributions : Design: AM, AFS, MW; Planning: AM; Data acquisition: AM MW; Data analysis: MW, AM, AFS; and Manuscript writing: AM, MW, AFS. All authors have approved submission of the final manuscript. Funding : The funding source for the present study was obtained from the St. Paul Institute for Reproductive Health and Rights (SPIRHR). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Conflict of interest : The authors have no conflicts of interest. Data sharing: Data available on request from authors References Anitha A, Rani BS. Comparison of fresh and frozen thawed embryo transfer in terms of clinical pregnancy rate. International Journal of Reproduction, Contraception, Obstetrics and Gynecology [Internet]. 2020 Feb 1 [cited 2024 Dec 16];9(2):607–13. Available from: https://go.gale.com/ps/i.do?p=HRCA&sw=w&issn=23201770&v=2.1&it=r&id=GALE%7CA652737739&sid=googleScholar&linkaccess=abs Bagheri RB, Bazrafkan M, Sabour A, Ataei M, Badehnoosh B, Mashak B, et al. The comparison of pregnancy outcomes in fresh and frozen embryo transfer: A cross-sectional study. International Journal of Reproductive BioMedicine. 2023;21(7):551. Vladimirov IK, Tacheva D, Dobrinov V. The present and future of embryo cryopreservation. 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Available from: https://www.sciencedirect.com/science/article/pii/S0015028217303631 Tables Table 1: Method of embryo transfer by baseline treatment characteristics Factor Level Type of embryo transfer p-value Fresh (n=149) Frozen (n=143) Age =35 years 67 (45.0%) 45 (31.5%) Type of infertility Primary 103 (69.1%) 117 (81.8%) 0.014 Secondary 46 (30.9%) 26 (18.2%) Previous live birth Yes 2 (1.3%) 20 (14.0%) <0.001 No 147 (98.7%) 123 (86.0%) Cause of infertility Female 68 (45.6%) 80 (55.9%) 0.013 Male 40 (26.8%) 23 (16.1%) Both 11 (7.4%) 3 (2.1%) Unexplained 30 (20.1%) 37 (25.9%) Method of sperm retrieval (n=63) Ejaculation 5 (13%) 5 (22%) 0.48 TESE 35 (88%) 18 (78%) Type of stimulation protocol Antagonist protocol 140 (94.0%) 125 (87.4%) 0.044 Long agonist protocol 1 (0.7%) 8 (5.6%) Minimal stimulation protocol 6 (4.0%) 9 (6.3%) Others 2 (1.3%) 1 (0.7%) Type of fertilization Conventional IVF 46 (30.9%) 54 (37.8%) 0.21 ICSI 103 (69.1%) 89 (62.2%) Grade of embryo on the day of embryo transfer Poor 10 (6.7%) 12 (8.4%) 0.014 Good 48 (32.2%) 25 (17.5%) Best 91 (61.1%) 106 (74.1%) * The p-value was calculated using the chi-square test to assess the association between categorical variables Table 2: Biochemical pregnancy outcome by baseline treatment characteristics Characteristics (n=292) Biochemical pregnancy (Serum HCG) result Positive (n=150) Negative (n=142) No. % No. % Age =35 years 49 32.7 63 44.4 Type of Embryo Transfer Fresh 58 38.7 91 64.1 Frozen 92 61.3 51 35.9 Type of infertility Primary 111 74.0 109 76.8 Secondary 39 26.0 33 23.2 Previous live birth Yes 17 11.3 5 3.5 No 133 88.7 137 96.5 Cause of infertility Female 74 49.3 74 52.1 Male 33 22.0 30 21.1 Both 9 6.0 5 3.5 Unexplained 34 22.7 33 23.2 Method of sperm cell retrieval (n=63) Ejaculation 7 21.2 3 10.0 TESE 26 78.8 27 90.0 Table 3: Different parameters by the type of embryo transfer Parameters Type of embryo transfer p-value* Fresh (149) Frozen (143) The total amount of gonadotropin used (in IU) till the day of trigger, median (IQR) 2700.0 (2400.0, 3375.0) 2700.0 (2100.0, 3075.0) 0.026 Total number of mature follicles (above 14mm) on the day of trigger, median (IQR) 5.0 (4.0, 8.0) 13.0 (9.0, 21.0) <0.001 Total number of oocytes collected on the day of OPU, median (IQR) 6.0 (4.0, 9.0) 16.0 (9.0, 23.0) <0.001 Number of M2 Oocytes, median (IQR) 4.0 (2.0, 6.0) 10.0 (6.0, 14.0) <0.001 Number of fertilized oocytes on day 3, median (IQR) 2.0 (1.0, 4.0) 0.0 (0.0, 3.0) <0.001 Number of blastocysts on day five, median (IQR) 0.0 (0.0, 0.0) 4.0 (0.0, 5.0) <0.001 Endometrial thickness on the day of trigger, median (IQR) 9.0 (8.0, 11.0) 10.0 (9.0, 12.0) 0.002 *Two-sample Wilcoxon rank-sum (Mann–Whitney) test was used to calculate the P value IQR= Interquartile range Table 4. Biochemical pregnancy by baseline characteristics Biochemical pregnancy (Serum HCG)result p-value* Positive (n=150) Negative (n=142) Age =35 years 49 (32.7%) 63 (44.4%) Type of Embryo Transfer Fresh 58 (38.7%) 91 (64.1%) <0.001 Frozen 92 (61.3%) 51 (35.9%) Type of infertility Primary 111 (74.0%) 109 (76.8%) 0.59 Secondary 39 (26.0%) 33 (23.2%) Previous live birth Yes 17 (11.3%) 5 (3.5%) 0.014 No 133 (88.7%) 137 (96.5%) Cause of infertility Female 74 (49.3%) 74 (52.1%) 0.79 Male 33 (22.0%) 30 (21.1%) Both 9 (6.0%) 5 (3.5%) Unexplained 34 (22.7%) 33 (23.2%) Method of sperm retrieval (n=63) Ejaculation 7 (21%) 3 (10%) 0.31 TESE 26 (79%) 27 (90%) Type of stimulation protocol Antagonist protocol 136 (90.7%) 129 (90.8%) 0.017 Long agonist protocol 8 (5.3%) 1 (0.7%) Minimal stimulation protocol 4 (2.7%) 11 (7.7%) Others 2 (1.3%) 1 (0.7%) Type of fertilization Conventional IVF 44 (29.3%) 56 (39.4%) 0.069 ICSI 106 (70.7%) 86 (60.6%) Grade of embryo on the day of embryo transfer Poor 9 (6.0%) 13 (9.2%) <0.001 Good 21 (14.0%) 52 (36.6%) Best 120 (80.0%) 77 (54.2%) Reasons for freezing the embryos (n=143) Left embryos after previous ET 51(55%) 24(47%) 0.49 Poor endometrial quality 14 (15%) 12 (24%) OHSS 18 (20%) 8 (16%) Hydrosalpinx 0 (0%) 1 (2%) Myoma 0 (0%) 1 (2%) High serum progesterone in the previous cycle 9 (10%) 5 (10%) * The p-value was calculated using the chi-square and Fisher’s exact test to assess the association between categorical variables Additional Declarations The authors declare no competing interests. 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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-9600436","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":633634746,"identity":"44e968eb-f8f2-427d-b15b-9391769a84f8","order_by":0,"name":"Ayalew Marye","email":"","orcid":"","institution":"St. Paul’s Hospital Millennium Medical College","correspondingAuthor":false,"prefix":"","firstName":"Ayalew","middleName":"","lastName":"Marye","suffix":""},{"id":633634766,"identity":"6c823c80-acd6-4f2e-a43b-fb96266c77e4","order_by":1,"name":"Mekitie Wondafrash","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABK0lEQVRIiWNgGAWjYFACNoYDDAYQpgSDDYhkPsAAFEnAq+UAXEsaiGRLIKgFaA2KFh6wCTi16La3JR7+UGDDYHC89+CNHwn35OVn93z+XFBwL8+8gfnYxy+YWszOHDsAdFgag8GZc8mWPQnFhhvunN0mPcOguFjmAFvybBksWm6kNwC1HAYycswkeH8kMG6QyN3GzGOQkDiDgceYWQKLlvvPQVr+g7VI/klIsJ8/I+fxZ7xabrCBHHYArEWaJyEhseFGDoM0TAvjB2x+SUs4cMYgmcf+zBlja5mEhOQNN9LMgH4BamFmS2bGEmJmx48Zf6j4Yycn2d5jePNNQoLt/BnJjz8X/AFqYW8+zPgDV1AzMPCg8JhhJDMPNsXYANw9+GwZBaNgFIyCEQMAHKNt3lN84S0AAAAASUVORK5CYII=","orcid":"https://orcid.org/0000-0002-8320-6244","institution":"St. Paul Institute for Reproductive Health and Rights","correspondingAuthor":true,"prefix":"","firstName":"Mekitie","middleName":"","lastName":"Wondafrash","suffix":""},{"id":633635058,"identity":"c1436493-7110-402f-a341-16d3c5fd5f6d","order_by":2,"name":"Abraham Fessehaye Sium","email":"","orcid":"https://orcid.org/0000-0001-5812-0804","institution":"St. Paul’s Hospital Millennium Medical College","correspondingAuthor":false,"prefix":"","firstName":"Abraham","middleName":"Fessehaye","lastName":"Sium","suffix":""}],"badges":[],"createdAt":"2026-05-03 14:05:33","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":false,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-9600436/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9600436/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108494158,"identity":"d47c1139-9680-4765-a781-3bcddb9a13eb","added_by":"auto","created_at":"2026-05-05 10:02:39","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":395414,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9600436/v1/907aec59-7922-4f4d-a004-8db6e061d2b2.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eIn vitro fertilization in a lower-middle-income country: success rates of frozen versus fresh embryo transfer-A retrospective cohort study\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eInfertility represents a significant global health challenge, affecting millions of couples worldwide and often necessitating the use of advanced assisted reproductive technologies (ART) such as in vitro fertilization (IVF)[1]. A critical decision in IVF treatment is the choice between fresh embryo transfer (ET) and frozen embryo transfer (FET). Historically, fresh ET was the predominant approach, characterized by the immediate transfer of embryos into the uterus following fertilization [2]. However, advances in cryopreservation techniques, including vitrification, have shifted the landscape toward FET, enabling the freezing and storage of embryos for later use [3]. This evolution has sparked ongoing debates regarding these two approaches' comparative efficacy and safety, with varying implications for clinical outcomes. Numerous factors influence the success rates of fresh and frozen embryo transfers, such as embryo quality, endometrial receptivity, and patient-specific characteristics, including age and underlying infertility conditions like polycystic ovary syndrome (PCOS). FET is often associated with reduced risks of ovarian hyperstimulation syndrome (OHSS), improved synchronization of the endometrial environment, and higher clinical pregnancy rates (CPR) in certain populations, such as high responders and those undergoing preimplantation genetic testing (PGT) [4,5]. Conversely, advocates for fresh ET emphasize its potential advantages, including a natural alignment between the embryo’s developmental stage and the uterine environment, which may enhance implantation success in specific cases [6,7]. \u0026nbsp;Moreover, fresh ET retains some advantages, including shorter treatment cycles and avoiding freezing-thawing processes, which might compromise embryo viability [8,9]. The ongoing debate over the optimal embryo transfer strategy is reflected in conflicting results from various studies. While randomized controlled trials and meta-analyses have demonstrated higher pregnancy and live birth rates with FET [10,11], other research highlights comparable or superior outcomes with fresh ET in specific populations, such as intermediate and low responders [6,12].\u003c/p\u003e\n\u003cp\u003eDespite extensive research, gaps remain in understanding the nuanced dynamics of fresh versus frozen embryo transfers, particularly in low-resource settings such as Ethiopia. Despite FET's growing popularity in high-income countries, its application in resource-limited environments remains underexplored[13,14], leaving questions about the applicability of findings in different socioeconomic and healthcare contexts. Factors such as patient demographics, resource availability, and clinical expertise may influence outcomes, underscoring the need for region-specific studies to inform practice and policy [4,15]. In addition to clinical outcomes such as pregnancy rates and live birth rates (LBR), the choice of embryo transfer method may also impact complications like OHSS and multiple pregnancies. Exploring these factors in diverse settings can contribute to optimizing ART protocols, improving patient care, and providing evidence-based recommendations for healthcare providers [16]. This study aimed at comparting \u0026nbsp; success rates of IVF treatments following fresh versus frozen embryo transfers.\u0026nbsp;\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy setting and period:\u003c/strong\u003e The study was conducted at Center for Reproductive Medicine (CFRM), the only government-owned center established in 2018 under St. Paul’s Hospital Millennium Medical College (SPHMMC), which provides comprehensive reproductive medicine and fertility care services to clients from Ethiopia and abroad. The center offers services including minimally invasive surgery, assisted reproductive techniques such as in vitro fertilization (IVF) and intrauterine insemination (IUI), as well as diagnostic workup and counseling for reproductive endocrinology and anomalies. On average, the center handles 1,000 IVF cycles annually. We collected data of patients who underwent embryo transfers between January 1, 2023, and December 31, 2023. To ensure data clarity, cases within three months of the data collection date were excluded, particularly for pregnancies at risk of subsequent complications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy designs\u003c/strong\u003e This study was an institution-based retrospective cohort study conducted at the CFRM of SPHMMC in Addis Ababa, Ethiopia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy population:\u003c/strong\u003e The source population included all women who underwent fresh embryo transfer (ET) or frozen embryo transfer (FET) at CFRM during the study period. The study population comprised women who met specific inclusion and exclusion criteria.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInclusion and exclusion criteria:\u0026nbsp;\u003c/strong\u003eThe inclusion criteria included women who underwent embryo transfer (fresh or frozen) between January 1, 2023, and December 31, 2023, with charts containing complete and clear documentation. Exclusion criteria encompassed women who did not proceed with embryo transfer after oocyte pick-up (OPU), those with an endometrial thickness outside the range of 7–14 mm, cases involving difficult embryo transfers, and women who discontinued luteal phase support (LPS) medications.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSample size calculation\u003c/strong\u003e: The sample size was calculated using the double population proportion formula for cohort studies. A study conducted in Iran in 2023 comparing fresh and frozen embryo transfers provided the basis for the calculation [2]: \u0026nbsp;n = (Z\u003csub\u003eα/2\u003c/sub\u003e+Z\u003csub\u003eβ\u003c/sub\u003e)\u003csup\u003e2\u003c/sup\u003e x (p1(1-p\u003csub\u003e1\u003c/sub\u003e) + p\u003csub\u003e2\u003c/sub\u003e(1-p\u003csub\u003e2\u003c/sub\u003e)) / (p\u003csub\u003e1\u003c/sub\u003e-p\u003csub\u003e2\u003c/sub\u003e)\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003ewhere Z\u003csub\u003eα/2\u003c/sub\u003e is the critical value of the Normal distribution at α/2 (for a confidence level of 95%, α is 0.05 and the critical value is 1.96), Z\u003csub\u003eβ\u003c/sub\u003e is the critical value of the Normal distribution at β (for a power of 80%, β is 0.2 and the critical value is 0.84) and p\u003csub\u003e1\u003c/sub\u003e= 54.3% and p\u003csub\u003e2\u003c/sub\u003e=70.8 are the expected sample proportions of the two groups. The calculated sample size was 296 participants, with 148 women in each group (fresh ET and frozen ET).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStudy variables:\u0026nbsp;\u003c/strong\u003eThe study examines various dependent and independent variables. \u0026nbsp;The dependent variables assessed are biochemical pregnancy, clinical pregnancy, the number of gestations, and the incidence of ovarian hyperstimulation syndrome (OHSS). The independent variables include sociodemographic factors, endometrial thickness, antral follicular count, the day of the embryo during transfer, the duration of freezing before embryo thawing, the clinician's level of expertise during the embryo transfer, the number of oocytes collected and fertilized, and the number of embryos transferred.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData collection and procedures\u003c/strong\u003e: Two trained research assistants abstracted data from patient records using a pretested structured data abstraction tool. When necessary, patients were contacted via the phone numbers provided in their charts to clarify incomplete or unclear information. Data were collected using KoboToolbox, and abstraction accuracy was monitored daily.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData analysis\u003c/strong\u003e Data analysis was performed using Stata 17 statistical software. Descriptive statistics, including percentages, means with standard deviations (SD), and medians with interquartile ranges (IQR), were calculated. Associations between independent and dependent variables were assessed using chi-square tests for categorical outcomes. For continuous outcomes, parametric (t-tests) and non-parametric (Mann-Whitney U tests) methods were employed, depending on data normality. Statistical significance was set at a p-value of \u0026lt;0.05, and results were presented in tables and graphs.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical considerations:\u003c/strong\u003e Ethical clearance was obtained from the Institutional Review Board (IRB) of SPHMMC. All information about the patients and their husbands was kept confidential, and no personal information was shared with third parties. Any needs for counseling, treatment, or appointments were addressed by phone. Information extracted from the medical charts was solely for data abstraction to answer the research question. The data collection process and other aspects of the study did not interfere with the women's or their husbands' treatment or follow-up. The researcher had no conflicts of interest with any individuals, groups, or pharmaceutical companies.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe study, which included 292 women undergoing fresh (n=149, 51%) and frozen (n=143, 49%) embryo transfers (ET), revealed several notable differences between the two groups. The mean age of women undergoing fresh cycles was 32.6 years (SD 4.86), slightly older than those in frozen cycles (31.7 years). A higher proportion of women aged ≥35 years end up in fresh ET (45% vs. 31.5%, p = 0.022), suggesting that older women were more likely to have fresh cycles. (Table 1). Primary infertility was more common in frozen cycles (81.8%) compared to fresh cycles (69.1%, p = 0.014). Additionally, the majority of women in the fresh group (98.7%) and frozen group (86%) had no previous live births, with a statistically significant difference favoring the frozen group (p \u0026lt; 0.001). Female factor infertility was the leading cause of infertility in both groups but was more prevalent in the frozen group (55.9% vs. 45.6%, p = 0.013). Unexplained infertility was the second most common cause in frozen cycles (25.9%), while male factor infertility was more frequent in fresh cycles (26.8% vs. 16.1%). Testicular Sperm Extraction (TESE) was a common sperm retrieval method for male factor infertility cases, used in 87.5% of fresh cycles and 78.3% of frozen cycles (Table 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe antagonist protocol was the predominant ovarian stimulation method in both groups (94% vs. 87.4%, p = 0.044), with higher usage in fresh cycles (Table 1). \u0026nbsp;The type of fertilization method varied slightly between groups, with Intracytoplasmic Sperm Injection (ICSI) being more common in fresh cycles (69.1% vs. 62.2%), while conventional IVF was more frequently used in frozen cycles (37.8% vs. 30.9%, p = 0.21; Table 1). Regarding embryo quality, a higher proportion of best-grade embryos was observed in frozen cycles (74.1% vs. 61.1%, p = 0.014; Table 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWomen in fresh cycles required a significantly higher total gonadotropin dose (median 3030.7 IU vs. 2558.2 IU, p = 0.026) and had fewer mature follicles on the day of the trigger (median 5 vs. 13, p \u0026lt; 0.001). Similarly, the total number of oocytes retrieved was significantly lower in fresh cycles (median 6 vs. 16, p \u0026lt; 0.001), as was the number of mature (M2) oocytes (median 4 vs. 10, p \u0026lt; 0.001). In addition, the number of blastocysts on day five was markedly higher in frozen cycles (median 4 vs. 0, p \u0026lt; 0.001; Table 3). The endometrial thickness on the day of the trigger was also slightly greater in frozen cycles (median 10 mm vs. 9 mm, p = 0.002) (Table 3).\u003c/p\u003e\n\u003cp\u003eBiochemical pregnancy outcomes revealed significant differences between the groups, with 61.3% of positive pregnancies occurring in frozen cycles compared to 38.7% in fresh cycles. Conversely, 64.1% of negative biochemical pregnancies were observed in fresh cycles compared to 35.9% in frozen cycles (p \u0026lt; 0.001; Table 2). Age significantly influenced pregnancy outcomes, as younger women (\u0026lt;35 years) had a higher proportion of positive biochemical pregnancies (67.3%, p = 0.042; Table 4). Among women with positive pregnancies, 88.7% had no prior live births, compared to 96.5% in those with negative outcomes (p =0.014; Table 4).\u003c/p\u003e\n\u003cp\u003eAmong women with positive biochemical pregnancies and after ultrasound examination at the eighth week, 127 (84.7%) had active fetuses on ultrasound, distributed as 91 singletons, 34 twins, and 2 triplets, while 12 (8%) had an empty uterus, and 11 (7.3%) had an anembryonic pregnancy (data not shown). Vaginal bleeding up to 10 weeks after embryo transfer was reported in 10 women (6.7%), whereas the majority (93.3%) did not experience bleeding. Frozen embryo transfers were performed for various reasons, including leftover embryos from previous transfers (55%), suboptimal endometrial quality (15%), and prevention of Ovarian Hyperstimulation Syndrome (OHSS; 20%; Table 4).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe main objective of this study was to compare the outcomes of fresh embryo transfer (ET) with that of frozen embryo transfer (FET) in vitro fertilization (IVF) in a low-middle income setting. We found superior clinical outcomes, including higher biochemical pregnancy rates and reduced risks of ovarian hyperstimulation syndrome (OHSS), in women who had IVF with frozen embryo transfer compared to those who had the same procedure with fresh embryo transfer. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAlthough existing evidence shows that frozen embryo transfer has more IVF success rate compared to Fresh embryo transfer [4,17], there is limited evidence on this topic from low-middle income countries such as the Sub-Saharan Africa region where infertility is more prevalent than any part of the world with IVF care services absents in most countries, especially at a public institution [18]. In the present study, compared to fresh embryo transfer, FET consistently showed higher success rates across all age groups, particularly among younger women, who experienced significantly higher positive biochemical pregnancy rates compared to their counterparts in fresh ET cycles.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAmong the interesting findings of this study, FET cycles required significantly lower gonadotropin dosages, produced more mature follicles, and yielded higher numbers of retrieved and fertilized oocytes, reinforcing the notion that FET protocols are less physically demanding and potentially more cost-effective in the long term [19]. The reduced rates of negative biochemical pregnancies and significantly higher rates of positive outcomes in FET also underscore its clinical advantages, particularly for high responders at risk of OHSS. Close to 9 in 10 women who had positive biochemical pregnancies in this study had no prior live births, highlighting the potential of FET to support first-time mothers in achieving successful pregnancies. Furthermore, the data on early pregnancy outcomes showed that 84.7% of pregnancies in this study had active fetuses on ultrasound, distributed as 91 singletons, 34 twins, and 2 triplets, while 93.3% of women reported no vaginal bleeding during early gestation. These findings provide additional support for the clinical effectiveness of FET in achieving favorable pregnancy outcomes.\u003c/p\u003e\n\u003cp\u003eStrengths of this study include being among the first to present on Frozen embryo transfer from low-middle income countries and proper sample size allocation. Incomplete documentation in some cases and the inability to account for inter-practitioner differences among clinicians and embryologists may have influenced the outcomes are the main limitations of this study. Future research should address these limitations and explore long-term maternal and neonatal outcomes associated with fresh and frozen ET protocols.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eOur study supports the growing preference for FET in IVF treatments, demonstrating its superior clinical outcomes in low-middle income country, particularly in terms of CPR and reduced OHSS risks. While fresh ET remains a viable option in specific clinical scenarios, individualized treatment planning based on patient characteristics and clinical history is essential. Further large-scale, multicenter randomized controlled trials are warranted to validate these findings and refine ART protocols, especially in resource-constrained settings like Ethiopia.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u003c/strong\u003e: Design: AM, AFS, MW; Planning: AM; Data acquisition: AM MW; Data analysis: MW, AM, AFS; and Manuscript writing: AM, MW, AFS. All authors have approved submission of the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: The funding source for the present study was obtained from the St. Paul Institute for Reproductive Health and Rights (SPIRHR). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e: The authors have no conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData sharing:\u003c/strong\u003e Data available on request from authors\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAnitha A, Rani BS. Comparison of fresh and frozen thawed embryo transfer in terms of clinical pregnancy rate. International Journal of Reproduction, Contraception, Obstetrics and Gynecology [Internet]. 2020 Feb 1 [cited 2024 Dec 16];9(2):607\u0026ndash;13. Available from: https://go.gale.com/ps/i.do?p=HRCA\u0026amp;sw=w\u0026amp;issn=23201770\u0026amp;v=2.1\u0026amp;it=r\u0026amp;id=GALE%7CA652737739\u0026amp;sid=googleScholar\u0026amp;linkaccess=abs\u003c/li\u003e\n\u003cli\u003eBagheri RB, Bazrafkan M, Sabour A, Ataei M, Badehnoosh B, Mashak B, et al. The comparison of pregnancy outcomes in fresh and frozen embryo transfer: A cross-sectional study. International Journal of Reproductive BioMedicine. 2023;21(7):551.\u003c/li\u003e\n\u003cli\u003eVladimirov IK, Tacheva D, Dobrinov V. The present and future of embryo cryopreservation. Embryology-Theory and Practice. 2018;\u003c/li\u003e\n\u003cli\u003eRoque M, Haahr T, Geber S, Esteves SC, Humaidan P. Fresh versus elective frozen embryo transfer in IVF/ICSI cycles: a systematic review and meta-analysis of reproductive outcomes. Human Reproduction Update [Internet]. 2019 Jan 1 [cited 2024 Dec 16];25(1):2\u0026ndash;14. Available from: https://doi.org/10.1093/humupd/dmy033\u003c/li\u003e\n\u003cli\u003eWeinerman R. Growth differences after fresh and frozen embryo transfers: When do they begin? Fertil Steril. 2021 Jul;116(1):75\u0026ndash;6.\u003c/li\u003e\n\u003cli\u003eAcharya KS, Acharya CR, Bishop K, Harris B, Raburn D, Muasher SJ. Freezing of all embryos in in\u0026nbsp;vitro fertilization is beneficial in high responders, but not intermediate and low responders: an analysis of 82,935 cycles from the Society for Assisted Reproductive Technology registry. Fertility and Sterility [Internet]. 2018 Oct 1;110(5):880\u0026ndash;7. Available from: https://www.sciencedirect.com/science/article/pii/S0015028218304254\u003c/li\u003e\n\u003cli\u003eDas PS, Banti M. Fresh Versus Frozen Embryo Transfer Among Women Undergoing Assisted Reproductive Technology: A Retrospective Cohort Study. Sarem Journal of Medical research [Internet]. 2021 Mar 10 [cited 2024 Dec 16];6(1):1\u0026ndash;8. Available from: http://saremjrm.com/article-1-197-en.html\u003c/li\u003e\n\u003cli\u003eGullo G, Basile G, Cucinella G, Greco ME, Perino A, Chiantera V, et al. Fresh vs. frozen embryo transfer in assisted reproductive techniques: a single center retrospective cohort study and ethical-legal implications. European Review for Medical \u0026amp; Pharmacological Sciences. 2023;27(14).\u003c/li\u003e\n\u003cli\u003eZhang J, Du M, Li Z, Wang L, Hu J, Zhao B, et al. Fresh versus frozen embryo transfer for full-term singleton birth: a retrospective cohort study. J Ovarian Res [Internet]. 2018 Jul 16 [cited 2024 Dec 16];11(1):59. Available from: https://doi.org/10.1186/s13048-018-0432-x\u003c/li\u003e\n\u003cli\u003eStormlund S, Sopa N, Zedeler A, Bogstad J, Pr\u0026aelig;torius L, Nielsen HS, et al. Freeze-all versus fresh blastocyst transfer strategy during in vitro fertilisation in women with regular menstrual cycles: multicentre randomised controlled trial. BMJ [Internet]. 2020 Aug 5 [cited 2024 Dec 16];370:m2519. Available from: https://www.bmj.com/content/370/bmj.m2519\u003c/li\u003e\n\u003cli\u003eSu Y, Zhang Y, Xu Z, Xu X, Xing Q, Zhang L, et al. Differences between fresh embryo transfer and frozen embryo transfer in Asian populations: a meta-analysis. Int J Clin Exp Med. 2018;11(9):8820\u0026ndash;30.\u003c/li\u003e\n\u003cli\u003eH. Petersen S, Westvik-Johari K, Spangmose AL, Pinborg A, Romundstad LB, Bergh C, et al. Risk of Hypertensive Disorders in Pregnancy After Fresh and Frozen Embryo Transfer in Assisted Reproduction: A Population-Based Cohort Study With Within-Sibship Analysis. Hypertension [Internet]. 2023 Feb [cited 2024 Dec 16];80(2):e6\u0026ndash;16. Available from: https://www.ahajournals.org/doi/full/10.1161/HYPERTENSIONAHA.122.19689\u003c/li\u003e\n\u003cli\u003eCoutifaris C. Freeze-only in vitro fertilization cycles for all? Fertility and Sterility [Internet]. 2017 Aug 1 [cited 2024 Dec 16];108(2):233\u0026ndash;4. Available from: https://www.fertstert.org/article/S0015-0282(17)30487-9/fulltext\u003c/li\u003e\n\u003cli\u003eWong KM, van Wely M, Mol F, Repping S, Mastenbroek S. Fresh versus frozen embryo transfers in assisted reproduction. Cochrane Database Syst Rev. 2017 Mar 28;3(3): CD011184.\u003c/li\u003e\n\u003cli\u003eDuarte-Filho OB, Podgaec S. Freeze-all policy for \u003cem\u003ein vitro\u003c/em\u003e fertilization in women with normal response to ovarian stimulation. einstein (S\u0026atilde;o Paulo) [Internet]. 2021 Oct 11 [cited 2024 Dec 16];19:eAO6290. Available from: https://www.scielo.br/j/eins/a/N5nDkczmLpTL3WBzZgbPKVh/?format=html\u0026amp;lang=en\u003c/li\u003e\n\u003cli\u003eBoynukalin FK, Turgut NE, Gultomruk M, Ecemis S, Yarkiner Z, Findikli N, et al. Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal \u0026amp; hyper responders? PLOS ONE [Internet]. 2020 Jun 26;15(6):e0234481. Available from: https://doi.org/10.1371/journal.pone.0234481\u003c/li\u003e\n\u003cli\u003eYang Y, Zhu D, Wang Q, Ma C, Li D, Wang J, et al. Frozen embryo transfer in the menstrual cycle after moderate-severe ovarian hyperstimulation syndrome: a retrospective analysis. BMC Pregnancy Childbirth [Internet]. 2022 Dec 6 [cited 2024 Dec 16];22(1):907. Available from: https://doi.org/10.1186/s12884-022-05239-0\u003c/li\u003e\n\u003cli\u003eSium AF, Gudu W, Bekele D. Infertility and fertility treatment options in sub‐Saharan Africa. International Journal of Gynecology \u0026amp; Obstetrics. 2025 May 7.\u003c/li\u003e\n\u003cli\u003eWang A, Santistevan A, Hunter Cohn K, Copperman A, Nulsen J, Miller BT, et al. Freeze-only versus fresh embryo transfer in a multicenter matched cohort study: contribution of progesterone and maternal age to success rates. Fertility and Sterility [Internet]. 2017 Aug 1 [cited 2024 Dec 16];108(2):254-261.e4. Available from: https://www.sciencedirect.com/science/article/pii/S0015028217303631\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1: Method of embryo transfer by baseline treatment characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFactor\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLevel\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of embryo transfer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFresh (n=149)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrozen (n=143)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAge\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e82 (55.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e98 (68.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.022\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026gt;=35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e67 (45.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e45 (31.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eType of infertility\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePrimary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e103 (69.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e117 (81.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSecondary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46 (30.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26 (18.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePrevious live birth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2 (1.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e20 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e147 (98.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e123 (86.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eCause of infertility\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e68 (45.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e80 (55.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.013\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e40 (26.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23 (16.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBoth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11 (7.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3 (2.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eUnexplained\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30 (20.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e37 (25.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMethod of sperm retrieval (n=63)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eEjaculation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (13%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5 (22%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.48\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTESE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e35 (88%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e18 (78%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eType of stimulation protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eAntagonist protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e140 (94.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e125 (87.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.044\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eLong agonist protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e8 (5.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMinimal stimulation protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6 (4.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9 (6.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eOthers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2 (1.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e1 (0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eType of fertilization\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eConventional IVF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e46 (30.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e54 (37.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.21\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eICSI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e103 (69.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e89 (62.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003eGrade of embryo on the day of embryo transfer\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePoor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10 (6.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e12 (8.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eGood\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e48 (32.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e25 (17.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e91 (61.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e106 (74.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*\u003cem\u003eThe p-value was calculated using the chi-square test to assess the association between categorical variables\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cem\u003e\u003cbr clear=\"all\"\u003e\u0026nbsp;\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2: Biochemical pregnancy outcome by baseline treatment characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCharacteristics (n=292)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eBiochemical pregnancy\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003cp\u003e\u003cstrong\u003e(Serum HCG) result\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePositive (n=150)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eNegative (n=142)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e%\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e101\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e67.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e55.6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026gt;=35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e32.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e63\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e44.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of Embryo Transfer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFresh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e58\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e38.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e91\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e64.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFrozen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e61.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e35.9\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of infertility\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003ePrimary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e111\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e74.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e109\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e76.8\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eSecondary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrevious live birth\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e11.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e88.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e137\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e96.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCause of infertility\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e49.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e74\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e52.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e22.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eBoth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3.5\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eUnexplained\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e22.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e23.2\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eMethod of sperm cell retrieval (n=63)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\u003cbr\u003e\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eEjaculation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e21.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTESE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e78.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e90.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3: Different parameters by the type of embryo transfer\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameters\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of embryo transfer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFresh (149)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eFrozen (143)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eThe total\u0026nbsp;amount of gonadotropin used (in IU) till the day of trigger, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2700.0\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(2400.0, 3375.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2700.0\u0026nbsp;\u003c/p\u003e\n \u003cp\u003e(2100.0, 3075.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.026\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTotal number of mature\u0026nbsp;follicles\u0026nbsp;(above 14mm) on the day of trigger, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e5.0 (4.0, 8.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e13.0 (9.0, 21.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eTotal number of oocytes collected on the day of OPU, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e6.0 (4.0, 9.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e16.0 (9.0, 23.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNumber of M2 Oocytes, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.0 (2.0, 6.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.0 (6.0, 14.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNumber of fertilized oocytes on day 3, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e2.0 (1.0, 4.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.0 (0.0, 3.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eNumber of\u0026nbsp;blastocysts\u0026nbsp;on day five, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.0 (0.0, 0.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e4.0 (0.0, 5.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003eEndometrial thickness on the day of trigger, median (IQR)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e9.0 (8.0, 11.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e10.0 (9.0, 12.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;*Two-sample Wilcoxon rank-sum (Mann\u0026ndash;Whitney) test was used to calculate the P value \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; IQR= Interquartile range\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4. Biochemical pregnancy by baseline characteristics\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 246px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eBiochemical pregnancy (Serum HCG)result\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ep-value*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003ePositive (n=150)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003eNegative (n=142)\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u003cem\u003e\u0026nbsp;\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u0026lt;35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e101 (67.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e79 (55.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.042\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u0026gt;=35 years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e49 (32.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e63 (44.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of Embryo Transfer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eFresh\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e58 (38.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e91 (64.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eFrozen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e92 (61.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e51 (35.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of infertility\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003ePrimary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e111 (74.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e109 (76.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.59\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eSecondary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e39 (26.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e33 (23.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePrevious live birth\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eYes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e17 (11.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e5 (3.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.014\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eNo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e133 (88.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e137 (96.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eCause of infertility\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e74 (49.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e74 (52.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.79\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e33 (22.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e30 (21.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eBoth\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e9 (6.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e5 (3.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eUnexplained\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e34 (22.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e33 (23.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMethod of sperm retrieval (n=63)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eEjaculation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e7 (21%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e3 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.31\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eTESE\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e26 (79%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e27 (90%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of stimulation protocol\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eAntagonist protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e136 (90.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e129 (90.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.017\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eLong agonist protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e8 (5.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e1 (0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eMinimal stimulation protocol\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e4 (2.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e11 (7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eOthers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e2 (1.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e1 (0.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eType of fertilization\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eConventional IVF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e44 (29.3%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e56 (39.4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.069\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eICSI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e106 (70.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e86 (60.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eGrade of embryo on the day of embryo transfer\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003ePoor\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e9 (6.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e13 (9.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eGood\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e21 (14.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e52 (36.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eBest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e120 (80.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e77 (54.2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eReasons for freezing the embryos (n=143)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eLeft embryos after previous ET\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e51(55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e24(47%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e0.49\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003ePoor endometrial quality\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e14 (15%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e12 (24%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eOHSS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e18 (20%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e8 (16%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eHydrosalpinx\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e1 (2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eMyoma\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e1 (2%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 276px;\"\u003e\n \u003cp\u003eHigh serum\u0026nbsp;progesterone\u0026nbsp;in the previous cycle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 120px;\"\u003e\n \u003cp\u003e9 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e5 (10%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 72px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*\u003cem\u003eThe p-value was calculated using the chi-square and Fisher\u0026rsquo;s exact test to assess the association between categorical variables\u003c/em\u003e\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"St. Paul’s Hospital Millennium Medical College","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"In vitro fertilization, Frozen embryo transfer, Fresh embryo transfer, Pregnancy outcomes","lastPublishedDoi":"10.21203/rs.3.rs-9600436/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9600436/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Infertility is a global health concern, often requiring in vitro fertilization (IVF). A key decision in IVF is choosing between fresh embryo transfer (ET) and frozen embryo transfer (FET). Advances in cryopreservation have shifted preference towards FET, yet debates about its comparative effectiveness persist. This study compares the success rates of IVF following fresh versus frozen ET at a Center for Fertility and reproductive medicine in Sub-Saharan Africa setting.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: This was a retrospective cohort study conducted at St. Paul’s Hospital Millennium Medical College, Addis Ababa, Ethiopia. Data from women undergoing fresh and frozen ET between January 1 and December 31, 2023, were analyzed. Variables included sociodemographic factors, infertility causes, treatment protocols, and pregnancy outcomes. The primary outcomes measured were biochemical pregnancy rates, clinical pregnancy rates, and live birth rates.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: A total of 292 women were included, with 149 undergoing fresh ET and 143 undergoing frozen ET. The mean age of women in fresh cycles was 32.6 years, compared to 31.7 years in frozen cycles. Female factor infertility was the most common cause in both groups, with higher prevalence in the frozen group (55.9% vs. 45.6%, p = 0.013). FET cycles showed better outcomes, with 74.1% of embryos graded as \"best\" compared to 61.1% in fresh cycles (p = 0.014). FET also required less gonadotropin (2558.2 IU vs. 3030.7 IU, p = 0.024) and yielded more mature follicles and oocytes (p \u0026lt; 0.001). Positive biochemical pregnancy rates were higher in the frozen group (61.3%, p \u0026lt; 0.001).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e: FET is associated with higher pregnancy rates, improved embryo quality, and reduced gonadotropin requirements compared to fresh ET. These findings support FET as a preferred approach in IVF, particularly for high responders and those at risk of ovarian hyperstimulation syndrome. Further research is needed on its long-term outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","manuscriptTitle":"In vitro fertilization in a lower-middle-income country: success rates of frozen versus fresh embryo transfer-A retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-05 03:48:15","doi":"10.21203/rs.3.rs-9600436/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fba85cc7-0187-4f8f-8cde-ad693523af0e","owner":[],"postedDate":"May 5th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":67443396,"name":"Obstetrics \u0026 Gynecology"}],"tags":[],"updatedAt":"2026-05-05T03:48:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-05 03:48:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9600436","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9600436","identity":"rs-9600436","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}