Adult Sex Ratio and Local Birth Rates in  Birhan Field Site, Amhara Region, Ethiopia

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Shiferaw, Delayehu B Mamo, Bezawit M. Hunegnaw, Clara Pons Duran, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5559868/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Oct, 2025 Read the published version in Scientific Reports → Version 1 posted 8 You are reading this latest preprint version Abstract Introduction: The study examined the adult sex ratio and fertility rate at Birhan Health and Demographic Surveillance System (HDSS) in the Amhara region of Ethiopia. Globally, the sex ratio at birth and total population remains stable, with approximately 105.6 boys born for every 100 girls and 101 males for every 100 females, respectively. Ethiopia's average population sex ratio is 101 males to 100 females. Fertility rates have declined globally since 1950, including in the Middle East, North Africa, and sub-Saharan Africa. Ethiopia's fertility rate decreased from 6.4 in 1990 to 4.6 in 2016. Method: The HDSS covers rural and urban areas, monitoring health and demographic conditions to provide an updated sampling frame for nested studies. Additionally, an open cohort study focused on maternal and under-two-year-old children's mortality and morbidity was conducted. Data from both the HDSS and the open cohort study were used to calculate key indicators, including Crude Birth Rate (CBR), General Fertility Rate (GFR), Total Fertility Rate (TFR), and Adult Sex Ratio (ASR). The study's strength lies in its comprehensive approach to pregnancy screening and birth outcome registration, yielding valuable data beyond traditional surveys. Result: The mid-year population was 72,776, with a higher number of males (38,454) than females (34,322). Among individuals aged 15–24 years, women made up 37.4% of the group, resulting in a sex ratio of 167.4 males per 100 females. For the broader reproductive age range (15–50 years), the sex ratio stood at 125 males per 100 females. In 2022, the TFR was 3.44 children per woman, reflecting a 25.22% decline compared to Ethiopia's national TFR of 4.6 in 2016. Other key fertility indicators also demonstrated notable reductions: the CBR was 19.98 per 1,000 population, and the GFR was 104.78 per 1,000 women of reproductive age, marking decreases of 37.24% and 32.83%, respectively, from the 2016 national averages. Conclusion: The findings highlight a youthful population with a higher male-to-female ratio, particularly among younger age groups. Fertility rates are notably lower compared to national figures. The lower fertility rate observed in these circumstances can be attributed to gendered migration patterns and the potential decrease in the risk of conception among migrants, stemming from improved living standards in urban areas and temporary separation from spouses. Health sciences/Health care Health sciences/Medical research The Total Fertility Rate Crude Birth Rate General Fertility Rate and Adult Sex Ratio Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Globally, the sex ratio at birth and the total population remains relatively stable, with 105.6 boys born for every 100 girls and 101.016 males for every 100 females, respectively. [ 1 ] This consistency is observed without deliberate manipulation. [ 2 ]Similarly, In Ethiopia, the average sex ratio at birth is 105.5 boys to 100 girls, while the population sex ratio stands at 101 males to 100 females.[ 3 ] Fertility refers to the ability of individuals or couples to reproduce through regular sexual activity.[ 4 , 5 ] Metrics like Crude Birth Rate (CBR), Total Fertility Rate (TFR), and General Fertility Rate (GFR) are used to measure fertility rates and population growth. [ 6 – 9 ] The demographers use to measure fertility per parent is the Total Fertility Rate (TFR). The TFR is the average number of children born to a woman over her lifetime if the woman were to experience the current age-specific fertility rates throughout her lifetime. It is a metric that captures the fertility rate in one particular year rather than over the life course of a generation of women. It's important to differentiate between birth rate (the number of live births per 1,000 total population) and total fertility rates. [ 5 , 9 ] The CBR represents the number of live births per 1,000 population. The GFR measures the number of live births per 1,000 women of reproductive age in a given year. To maintain a stable population in a given area—without factoring in immigration or emigration—a total fertility rate (TFR) of 2.1 children per woman is generally required. [ 5 ] While many regions worldwide still report fertility rates well above this replacement level, the global TFR has declined markedly since 1950. Between 1950 and 1955, the global average fertility rate was 4.97 children per woman. This decreased to 3.86 in 1975–1980 and further to 2.5 in 2005–2010. By 2021, it had dropped to 2.32. [ 9 ] A pooled analysis of 33 sub-Saharan African countries estimated the overall fertility rate at five children per woman (95% CI: 4.63–5.37). Fertility rates were higher in low-income countries (5.45) compared to lower-middle-income (4.70) and upper-middle-income countries (3.80). Between 2010 and 2018, the TFR varied across African regions: East Africa reported 4.74, Central Africa 5.59, Southern Africa 3.18, and West Africa 5.38 children per woman.[ 10 ] Fertility is crucial in shaping population dynamics, influencing a population's size and structure. As in many Sub-Saharan African countries, high fertility rates have contributed to rapid population growth in Ethiopia. Prior to the 1990 National Family and Fertility Survey (NFFS), detailed fertility data was scarce.[ 11 ] Since then, the Ethiopian Health and Demographic Surveys (EDHS) have filled this data gap. Ethiopia's total fertility rate (TFR) has steadily declined from 6.4 children per woman in 1990 to 4.6 children per woman in 2016. The TFR trends, according to the NFFS and EDHS, were 6.4 in 1990, 5.9 in 2000, 5.4 in 2005, 4.8 in 2011, 4.1 in 2014, and 4.6 in 2016. By 2016, the national average showed a reduction of 1.3 children per woman compared to 2000. However, the decline was even more pronounced in the Amhara region, where the TFR decreased by 2.2 children per woman. The TFR trends in Amhara were 5.9 in 2000, 5.1 in 2005, 4.2 in 2011, and 3.7 in 2016. [ 11 – 16 ] The data reveals a declining trend in both the General Fertility Rate (GFR) and the Crude Birth Rate (CBR) over the years. The GFR decreased steadily from 193 in 2000 to 156 in 2016, indicating a gradual reduction in the number of births per 1,000 women of reproductive age. Similarly, the CBR showed a consistent decline from 41.3 in 2000 to 31.8 by 2016, maintaining the same level through 2022. These trends suggest a significant shift in fertility patterns over the past two decades, possibly reflecting factors such as improved access to family planning, increased female education and workforce participation and changing socio-economic conditions influencing reproductive behavior.[ 12 – 14 , 16 , 17 ] The most critical factor in population growth is the TFR. When women, on average, have 2.1 children who survive until the age of 15, each woman will replace herself and her partner upon death. Conversely, if the TFR falls below 2.1, the population in a given area will eventually decline, although it may take time due to age structure, emigration, and immigration.[ 5 , 18 ] Ethiopia is a prominent source country for young women migrants to the Middle East's domestic labor market.[ 19 , 20 ] Among the regions most heavily impacted by this migration is the Amhara region, where many young women leave in search of employment opportunities abroad.[ 21 ] This gendered migration contributes to unusually high adult-sex ratios (ASR) [ 10 ] which, in turn, influences female fertility patterns by delaying marriage or causing prolonged separation from spouses. Additionally, the emigration of young women may have broader demographic impacts on fertility rates. Because in impoverished areas, a higher proportion of females often leads to increased birth rates.[ 22 ] In Ethiopia, vital event registration is almost nonexistent, and key indicators such as sex ratio and fertility rate were not included in the 2019 EDHS survey. [ 23 ] Due to this gap, important migration-related demographic characteristics—particularly fertility rates and sex ratios - have not been studied in regions like Amhara despite it being one of the most heavily impacted areas. To address this, the Birhan HDSS aims to provide updated demographic information by analyzing adult sex ratios and fertility rates within its study population, using existing surveillance data to offer valuable insights into the population structure and demographic conditions of the Amhara region in Ethiopia. Objective To evaluate the Adult Sex Ratio and key fertility indicators within the Birhan HDSS site in the Amhara region of Ethiopia from Dec 1, 2021, to Nov 30, 2022. Methods The Birhan Field site was established in June 2018 through a collaboration between Saint Paul's Hospital Millennium Medical College (SPHMMC) and Harvard School of Public Health (HSPH) in the North Shewa Zone of the Amhara Region, Ethiopia. The study area includes a health and demographic surveillance system (HDSS), which includes fourteen rural and two urban kebeles (the smallest administrative units used in Ethiopia) (Figure: 1) . The primary objectives of this surveillance system are to ensure continuous and ongoing monitoring of the health and demographic conditions of the population in the area and to serve as a valuable resource as it provides a well-defined population sampling frame to conduct nested studies. The primary activity of the Birhan Health and Demographic Surveillance System (HDSS) consists of systematically conducting house-to-house visits within the surveillance area at regular three-month intervals. These visits are designed to actively monitor and update detailed information on both individual members and household-level dynamics, including births, deaths, migrations, marital status changes, and other demographic events. If new households have been established within the village - either through immigration or household formation - these households are identified, and comprehensive baseline data are collected. Once baseline information is gathered, these households are formally enrolled in the HDSS and become part of the ongoing surveillance system. In addition to capturing routine demographic events, the HDSS data collectors play a critical role in the early identification of pregnancies within the community. [ 24 ] The study team developed a Tangerine-based electronic data system for longitudinal data collection to support this process. This system operates in two ways: when syncing, the Tangerine Collect app allows data collectors to both upload (push) and download (pull) data from the Tangerine Aggregate central database. Data collected on tablets is regularly uploaded to the central database, and updates from the database are downloaded to the tablets whenever data collectors sync them, typically daily. Within the HDSS population, there was a nested pregnancy and birth Birhan open cohort study, to estimate the causes of children and maternal mortality and morbidity. In this study, Women of reproductive age are regularly monitored for pregnancy screening by the cohort and HDSS data collectors, community key informants at the household level, and healthcare providers at health facilities within the catchment area. The woman is referred to the Birhan open cohort study team if a pregnancy is detected. Pregnant women who consented were enrolled and followed through antenatal, birth, and two years post-partum, conducting scheduled visits to assess their health and well-being throughout pregnancy, delivery, and the postnatal period. The central database served as a bridge for the HDSS and nested studies; updates made on each study participant were displayed for Birhan open cohort data collectors on a daily basis. [ 25 ] We extracted one year data (December 1, 2021, to November 30, 2022) from the HDSS and the Birhan Cohort. From the HDSS, we collected information on the average population of the study area during the study year and the number of women of reproductive age. Furthermore, we obtained the number of live births from the HDSS and the morbidity and mortality cohort datasets. With this data, we calculated key indicators related to fertility rates and ASR. The CBR represents the number of live births per 1,000 population. The GFR measures the number of live births per 1,000 women of reproductive age. The TFR estimates the average number of children a woman would have in her lifetime based on current birth rates. In addition to fertility indicators, we also calculated the ASR. The adult sex ratio represents the ratio of males to females in the adult population (15–49 years old). Our analytical strategies for measuring human fertility and ASR in the study area are based on descriptive statistics and involve the use of the following methods: Crude Birth Rate (CBR): The CBR is calculated by dividing the total number of live births recorded in a population over a year by the mid-year population and then multiplying by 1,000. CBR = (Total number of children born in a year) / (Mid-year Population) x 1000.[ 8 ] The GFR is calculated by dividing the total number of births per year by the female population in the reproductive age group and multiplying by 1,000. GFR = (Total number of children born in a year) / (Female Population, ages 15–49) x 1000.[ 9 ] The TFR measures the average number of children each woman would have over her reproductive age if the age-specific birth rates remain constant. It is calculated by summing the age-specific birth rates (ASFR) for each age group (e.g., 15–19, 20–24, 25–29, … 45–49) and multiplying by 5. TFR = 5 * ∑(ASFR).[ 6 ] The ASR is calculated by dividing the number of adult males (15–49 years old) by the number of adult females (15–49 years old) and multiplying by 100. We obtained protocol approvals for both the HDSS and open cohort studies from the Institutional Review Boards (IRB) of Saint Paul's Hospital Millennium Medical College (SPHMMC) and Harvard T.H. Chan School of Public Health (HSPH). All methods were carried out in accordance with these approved protocols. Result The Birhan Health and Demographic Surveillance System (HDSS) findings for the study period (December 1, 2021 – November 30, 2022) provide valuable insights into the population structure. The mid-year population was 72,776, with more males (38,454) than females (34,322). The population pyramid reflects a predominantly young population, characterized by a broad base representing a large proportion of children and adolescents. Population numbers decline with increasing age, a pattern typical in developing regions. Notably, the population pyramid highlights a skewed sex ratio favoring males in the 15–25-year age group ( Figure: 2 ). Specifically, women made up 37.4% of the 15–24-year age group, resulting in a sex ratio of 167.4 males for every 100 females. Across the broader reproductive age group (15–50 years), the sex ratio was 125 males per 100 females. Overall, the study area exhibited a male-dominant population, with 112 males for every 100 females ( Table: 1 ) Table 1: Sex Ratio in Birhan HDSS Study Population in Amhara Region, Ethiopia, 2022 Age group Male Female Sex Ratio 50 5,088 5565 47.8 15–50 19,466 15,554 55.6 Total 38,454 34,322 52.8 The population of women of reproductive age (WRA) in the study area totaled 14,086, among whom 1,476 live births occurred, comprising 748 boys and 728 girls. This results in a sex ratio at birth of 102.7 boys for every 100 girls, which is consistent with natural sex ratio patterns observed globally. Fertility rates were highest among women aged 20 to 34 years, reflecting both biological factors and prevailing social norms regarding childbearing. Specifically, women in the 25–29 age group had the highest number of live births (424), followed closely by those aged 30–34 years (399) and 20–24 years (322). Fertility declined substantially after age 35, with markedly lower rates among women aged 40–49 years. Compared to national trends, the fertility rate in the Birhan HDSS population has declined. The Total Fertility Rate (TFR) for 2022 was 3.44 children per woman, lower than Ethiopia’s national TFR of 4.6 in 2016 and significantly lower than the 6.4 recorded in 1990. The decline in fertility is also evident across all age-specific fertility rates (ASFRs), with adolescent fertility (ages 15–19) notably lower in Birhan HDSS (22 per 1,000 women) compared to the national rates reported in previous Ethiopian Demographic and Health Surveys (EDHS) ( Table: 2 & Figure: 3 ). Table 2: Trends in Fertility Rates Trends in ASFRs (per 1000 women) and TFRs in Ethiopia from 2000–2016 and in Birhan HDSS in Amhara Region, Ethiopia, 2022 Birhan HDSS study population Age group NFFS 1990 EDHS 2000 EDHS 2005 EDHS 2011 EDHS 2016 2022 * WRA** Live births*** 15–19 95 110 104 79 80 22 2276 50 20–24 275 244 228 207 214 173 1859 322 25–29 289 264 241 237 190 192 2213 424 30–34 257 248 231 192 190 155 2578 399 35–39 199 183 160 150 138 90 2022 182 40–44 105 100 84 68 69 45 1895 85 45–49 56 24 34 28 22 11 1244 14 Total 6.4 5.900 5.5 4.8 4.6 3.44 14086 1476 * Aage-specific and total fertility rates in Brihan HDSS. ** Number of women of reproductive age in each age group Brihan HDSS. *** Number of live births in each age group Brihan HDSS. The fertility analysis of the Birhan HDSS study population in 2022 reveals a decline in fertility indicators when compared to previous national averages. The Total Fertility Rate (TFR) was 3.44 children per woman, representing a 25.22% reduction from Ethiopia’s national TFR of 4.6, as reported in the 2016 Ethiopian Demographic and Health Survey (EDHS). Similarly, the Crude Birth Rate (CBR) in Birhan HDSS was 19.98 births per 1,000 population, which is 37.24% lower than the national average of 31.84 per 1,000 reported in 2016. The General Fertility Rate (GFR), which measures the number of live births per 1,000 women of reproductive age (15–49 years), was also lower in Birhan, at 104.78, compared to the national figure of 156 in 2016. This represents a decrease of 32.83%. These reductions across key fertility indicators TFR, CBR, and GFR highlight an overall decline in fertility in the Birhan HDSS area relative to national trends observed over the past two decades (Table: 3 & Figure: 4). Table 3 CBR, GFR, and TFR in Ethiopia from 2000–2016 and in Birhan HDSS Study Population in Amhara Region, Ethiopia, 2022 Fertility measures EHDS 2000* EDHS 2005* EDHS 2011* EDHS 2016** Birhan HDSS 2022** Difference (** - *) GFR 193 179 161 156 104.784 -32.83% CBR 41.3 35.7 34.5 31.84 19.984 -37.24% TFR 5.900 5.5 4.8 4.6 3.44 -25.22% * Fertility measures in Ethiopia EDHS ** Fertility measures of Birhan HDSS Study Population in Amhara Region, Ethiopia, 2022 ** - * The difference in fertility measures between Ethiopia in EDHS 2016 and Birhan HDSS 2022 Discussions The study, conducted in Birhan HDSS, Amhara region, Ethiopia, examined adult sex ratios and fertility rates. Among those aged 15–24, women made up only 37.4%, with a sex ratio of 167.4 males per 100 females. For women aged 15–50, the sex ratio was 125 males per 100 females. In 2022, the TFR was 3.44 children per woman, a 25.22% decline from Ethiopia’s national TFR of 4.6 in 2016. Other fertility indicators also dropped: the CBR was 19.98 per 1,000 population (down 37.24%), and GFR was 104.78 per 1,000 women of reproductive age (down 32.83%) compared to 2016 national figures[ 16 ]. The global average total fertility rate has declined over the years. In 1950-55, 1975-80, and 2005-10, the rates were 4.97, 3.86, and 2.5 children per woman, respectively. By 2021, it had further dropped to 2.32. [ 9 ] This fertility reduction caused the global population to decrease from 2% in the 1970s to 1.1% in 2017. [ 26 ] In East Africa, the pooled estimates indicate a total fertility rate of 4.74 children per woman [ 10 ], and the population growth rates reached their highest reported levels in 2017, at 2.7%. [ 26 ] Total fertility rate dropping from 5.9 in 2000 to 4.6 in 2016. The Birhan HDSS population exhibited an even greater decline, with a TFR of 25.22% lower than the national average in 2016. This figure is comparable to the TFR of the Amhara region, which stood at 3.7 in 2016—approximately 7% higher than Birhan’s—indicating similar lifetime fertility levels. The Amhara region’s TFR decreased from 5.9 in 2000 to 3.7 in 2016, with intermediate values of 5.1 in 2005 and 4.2 in 2011. [ 12 – 14 , 16 ] National trends show a consistent reduction in fertility rates, and a 7% difference in TFR over six years aligns with these patterns. Although the Ethiopian Demographic and Health Surveys (EDHS) do not provide Crude Birth Rate (CBR) and General Fertility Rate (GFR) data at the regional level, the observed reductions are significant, amounting to a 37.24% decrease in CBR and a 32.83% decrease in GFR since 2016. [ 16 ] This substantial decline highlights the importance of TFR as a robust measure of fertility, as it is the least affected by variations in the sex ratio. The total fertility rate reflects fertility behavior per woman rather than being influenced by the absolute number of women or men in the population[ 27 , 28 ]. The migration of young women seems to be reducing the number of women of reproductive age in areas like Birhan HDSS. This trend is part of a broader urban transition in Ethiopia, where rural women often migrate abroad to earn money for future moves to towns. [ 19 ] [ 19 , 20 , 29 ] Higher sex ratios and lower birth rates are observed, partly due to fewer young women who typically have children earlier, with a median age at first birth of 18.7. This is because poorer women tend to give birth at younger ages [ 22 ], and with a median age at first birth of 18.7.[ 23 , 30 ] Migration also impacts women's health; 29.2% of returnees from the Middle East experience common mental disorders. Additionally, migrants have lower conception rates during and after migration, influenced by temporary separation from partners and improved living conditions post-migration. [ 31 ]. Furthermore, migrants have a lower risk of conception during the migration period and often maintain lower conception rates than non-migrants in the long run. This could be due to the improvement in living standards experienced by migrants after settling in urban areas and the temporary separation from spouses.[ 32 ] Strengths of the study The Birhan HDSS examined pregnancies and recorded birth outcomes for women of reproductive age four times during the study year. Community health workers also screened pregnancies in villages. A separate study team closely monitored pregnant women throughout childbirth, documenting birth outcomes at both the household and facility levels. This comprehensive approach to pregnancy screening and birth outcome registration offers greater value than surveys. Limitation of the study The study didn’t quantify the exact migration figure over the study period in the study area, and this is our recommendation for future research. Conclusion The findings reveal a young population with a higher male-to-female ratio, especially in younger age groups. Fertility rates are significantly lower than national averages, likely due to gendered migration and reduced conception risks among migrants linked to better living conditions in urban areas and temporary separation from partners. A key strength of the study is its thorough pregnancy screening and birth outcome tracking, offering more accurate data than traditional surveys. Monitoring these trends is essential for informed demographic planning and policymaking to support sustainable development. Abbreviations ASFR: Age-Specific Birth Rates, ASR: Adult Sex Ratio, BSc: Bachelor of Science, CBR: Crude Birth Rate, EDHS: Ethiopian Health and Demographic Surveys, GFR: General Fertility Rate, HDSS: Health and Demographic Surveillance System, HSPH: Harvard T.H. Chan School of Public Health, IRB: Institutional Review Board, MD: Medical Doctor, MPH: Master of Public Health, MSc: Master of Science, PhD: Doctor of Philosophy, National Family and Fertility Survey (NFFS), SPHMMC: Saint. Paul’s, Hospital Millennium Medical College, TFR: Total Fertility Rate, USA: United States of America. Declarations Ethics approval and consent to participate The Institutional Review Board (IRB) of SPHMMC and HSPH granted ethical clearance, and verbal consent was secured from all respondents. Consent for Publication All study participants gave informed consent, confirming their willingness to contribute to the research findings. Availability of data and materials The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request. Competing interests The authors declare that they have no competing interests. Funding This work has been supported by the Bill & Melinda Gates Foundation (grants INV-010382, INV-003612, and INV-006752) through the HaSET Maternal and Child Health Research Program. Authors' Contributions CB prepared the study materials, monitored the data collection process, contributed to data analysis, and drafted the manuscript. DB, CD, KA, and BM participated in preparing study materials, data collection, and manuscript development. FA and YM designed an electronic data collection system, oversaw the data collection process, analyzed the data, and contributed to the manuscript. GC supervised and approved the study materials, analysis plan, and final manuscript. 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Shiferaw","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIie3PIQvCUBDA8dODWzl59Q1ln2EyMIl+FWVgshk1DAZaRKsgfgc/wuTBkmAdaJgKJsMsYhAVi8EwZxN8/3BcuB+PB6DT/WISCCCAEiAu4ueWmTAY5NpfEsEVmYmIqUdxsqyyQKh0ubexBOB2F6U9sgmM8iRqselDa83hwTE9cpx2CrFlg4qcKLYVhGsm1ZwHTMWP5Jrcua5y/Q7fshKIArYRCQv9DERGzUF5uHRZKkJzNlKO6X/4i5i4YXwJa5YYr07J8awsYfjbfRoByHmvNc/Piann7/ryzbVOp9P9TQ+CKUojRimiIgAAAABJRU5ErkJggg==","orcid":"","institution":"Birhan Field Site , Saint. Paul’s Hospital Millennium Medical College, Addis Ababa","correspondingAuthor":true,"prefix":"","firstName":"Chalachew","middleName":"B.","lastName":"Shiferaw","suffix":""},{"id":440648989,"identity":"04d44383-f293-43a1-a053-2b8700e1933f","order_by":1,"name":"Delayehu B Mamo","email":"","orcid":"","institution":"Department of Obstetrics and Gynecology, St. Paul’s Hospital Millennium Medical College, Addis Ababa","correspondingAuthor":false,"prefix":"","firstName":"Delayehu","middleName":"B","lastName":"Mamo","suffix":""},{"id":440648990,"identity":"fbd12148-bcde-4c43-8037-40398602670c","order_by":2,"name":"Bezawit M. Hunegnaw","email":"","orcid":"","institution":"HaSET Maternal and Child Health Research Program, Addis Ababa","correspondingAuthor":false,"prefix":"","firstName":"Bezawit","middleName":"M.","lastName":"Hunegnaw","suffix":""},{"id":440648991,"identity":"4d8112a9-1d5c-4e8d-9e33-c7808b02c48a","order_by":3,"name":"Clara Pons Duran","email":"","orcid":"","institution":"Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA","correspondingAuthor":false,"prefix":"","firstName":"Clara","middleName":"Pons","lastName":"Duran","suffix":""},{"id":440648992,"identity":"ef4dd731-9ee4-429a-bede-9071f859f9e7","order_by":4,"name":"Fanos Ashenafi","email":"","orcid":"","institution":"HaSET Maternal and Child Health Research Program, Addis Ababa","correspondingAuthor":false,"prefix":"","firstName":"Fanos","middleName":"","lastName":"Ashenafi","suffix":""},{"id":440648993,"identity":"36e8bac9-1046-4e26-869c-064245882165","order_by":5,"name":"Yahya Mohammed","email":"","orcid":"","institution":"HaSET Maternal and Child Health Research Program, Addis Ababa","correspondingAuthor":false,"prefix":"","firstName":"Yahya","middleName":"","lastName":"Mohammed","suffix":""},{"id":440648994,"identity":"f34ece94-8c45-4b8b-b60d-b096ded80005","order_by":6,"name":"Kassahun Alem","email":"","orcid":"","institution":"College of Medicine and Health Sciences, the University of Gondar and Senior Research and Fellowship Advisor, HaSET, Gondar","correspondingAuthor":false,"prefix":"","firstName":"Kassahun","middleName":"","lastName":"Alem","suffix":""},{"id":440648995,"identity":"c470343a-7f59-4510-806e-9231ae701a3a","order_by":7,"name":"Grace J. Chan","email":"","orcid":"","institution":"Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA","correspondingAuthor":false,"prefix":"","firstName":"Grace","middleName":"J.","lastName":"Chan","suffix":""}],"badges":[],"createdAt":"2024-12-01 19:23:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5559868/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5559868/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41598-025-20750-y","type":"published","date":"2025-10-22T16:17:27+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":80580215,"identity":"433a0d15-13f3-4a73-bee3-0554b34bf3c7","added_by":"auto","created_at":"2025-04-14 23:14:14","extension":"jpeg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":69478,"visible":true,"origin":"","legend":"\u003cp\u003eMap of the Birhan Health and Demographic Surveillance System\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-5559868/v1/047ff5fbafe78f276ab0a30c.jpeg"},{"id":80580216,"identity":"765cb026-a25a-4cf7-8bf3-5ff01df32b0f","added_by":"auto","created_at":"2025-04-14 23:14:14","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":37263,"visible":true,"origin":"","legend":"\u003cp\u003ePopulation Pyramid of Birhan HDSS 2022 midyear population\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-5559868/v1/1a08780bb313970537f1a335.png"},{"id":80580226,"identity":"ccc3752e-236f-4650-9853-14788561f3d3","added_by":"auto","created_at":"2025-04-14 23:14:14","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":14620,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cem\u003eTrends in ASFRs (per 1000 women) and TFRs in Ethiopia from 2000 – 2016 and in Birhan HDSS in Amhara Region, Ethiopia, 2022\u003c/em\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-5559868/v1/370b5ca094b2764278e830e3.png"},{"id":80577644,"identity":"10476302-9c41-4914-a360-7380c3ad93a8","added_by":"auto","created_at":"2025-04-14 22:58:14","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":161296,"visible":true,"origin":"","legend":"\u003cp\u003eTrend Analysis Fertility Measures\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-5559868/v1/363a3edc59a1501a0dec3cd0.png"},{"id":94490421,"identity":"63279aa9-fe10-485d-b241-1d676e76dc7a","added_by":"auto","created_at":"2025-10-27 17:09:56","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1047092,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5559868/v1/a587792c-c225-4969-b2b2-9da57ec46ce2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Adult Sex Ratio and Local Birth Rates in Birhan Field Site, Amhara Region, Ethiopia","fulltext":[{"header":"Introduction","content":"\u003cp\u003eGlobally, the sex ratio at birth and the total population remains relatively stable, with 105.6 boys born for every 100 girls and 101.016 males for every 100 females, respectively. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] This consistency is observed without deliberate manipulation. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]Similarly, In Ethiopia, the average sex ratio at birth is 105.5 boys to 100 girls, while the population sex ratio stands at 101 males to 100 females.[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eFertility refers to the ability of individuals or couples to reproduce through regular sexual activity.[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] Metrics like Crude Birth Rate (CBR), Total Fertility Rate (TFR), and General Fertility Rate (GFR) are used to measure fertility rates and population growth. [\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] The demographers use to measure fertility per parent is the \u003cem\u003eTotal\u003c/em\u003e Fertility Rate (TFR). The TFR is the average number of children born to a woman over her lifetime if the woman were to experience the current age-specific fertility rates throughout her lifetime. It is a metric that captures the fertility rate in one particular year rather than over the life course of a generation of women. It's important to differentiate between birth rate (the number of live births per 1,000 total population) and total fertility rates. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] The CBR represents the number of live births per 1,000 population. The GFR measures the number of live births per 1,000 women of reproductive age in a given year.\u003c/p\u003e \u003cp\u003eTo maintain a stable population in a given area\u0026mdash;without factoring in immigration or emigration\u0026mdash;a total fertility rate (TFR) of 2.1 children per woman is generally required. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] While many regions worldwide still report fertility rates well above this replacement level, the global TFR has declined markedly since 1950. Between 1950 and 1955, the global average fertility rate was 4.97 children per woman. This decreased to 3.86 in 1975\u0026ndash;1980 and further to 2.5 in 2005\u0026ndash;2010. By 2021, it had dropped to 2.32. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] A pooled analysis of 33 sub-Saharan African countries estimated the overall fertility rate at five children per woman (95% CI: 4.63\u0026ndash;5.37). Fertility rates were higher in low-income countries (5.45) compared to lower-middle-income (4.70) and upper-middle-income countries (3.80). Between 2010 and 2018, the TFR varied across African regions: East Africa reported 4.74, Central Africa 5.59, Southern Africa 3.18, and West Africa 5.38 children per woman.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eFertility is crucial in shaping population dynamics, influencing a population's size and structure. As in many Sub-Saharan African countries, high fertility rates have contributed to rapid population growth in Ethiopia. Prior to the 1990 National Family and Fertility Survey (NFFS), detailed fertility data was scarce.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] Since then, the Ethiopian Health and Demographic Surveys (EDHS) have filled this data gap. Ethiopia's total fertility rate (TFR) has steadily declined from 6.4 children per woman in 1990 to 4.6 children per woman in 2016. The TFR trends, according to the NFFS and EDHS, were 6.4 in 1990, 5.9 in 2000, 5.4 in 2005, 4.8 in 2011, 4.1 in 2014, and 4.6 in 2016. By 2016, the national average showed a reduction of 1.3 children per woman compared to 2000. However, the decline was even more pronounced in the Amhara region, where the TFR decreased by 2.2 children per woman. The TFR trends in Amhara were 5.9 in 2000, 5.1 in 2005, 4.2 in 2011, and 3.7 in 2016. [\u003cspan additionalcitationids=\"CR12 CR13 CR14 CR15\" citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe data reveals a declining trend in both the General Fertility Rate (GFR) and the Crude Birth Rate (CBR) over the years. The GFR decreased steadily from 193 in 2000 to 156 in 2016, indicating a gradual reduction in the number of births per 1,000 women of reproductive age. Similarly, the CBR showed a consistent decline from 41.3 in 2000 to 31.8 by 2016, maintaining the same level through 2022. These trends suggest a significant shift in fertility patterns over the past two decades, possibly reflecting factors such as improved access to family planning, increased female education and workforce participation and changing socio-economic conditions influencing reproductive behavior.[\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe most critical factor in population growth is the TFR. When women, on average, have 2.1 children who survive until the age of 15, each woman will replace herself and her partner upon death. Conversely, if the TFR falls below 2.1, the population in a given area will eventually decline, although it may take time due to age structure, emigration, and immigration.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eEthiopia is a prominent source country for young women migrants to the Middle East's domestic labor market.[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e] Among the regions most heavily impacted by this migration is the Amhara region, where many young women leave in search of employment opportunities abroad.[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] This gendered migration contributes to unusually high adult-sex ratios (ASR) [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] which, in turn, influences female fertility patterns by delaying marriage or causing prolonged separation from spouses. Additionally, the emigration of young women may have broader demographic impacts on fertility rates. Because in impoverished areas, a higher proportion of females often leads to increased birth rates.[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn Ethiopia, vital event registration is almost nonexistent, and key indicators such as sex ratio and fertility rate were not included in the 2019 EDHS survey. [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] Due to this gap, important migration-related demographic characteristics\u0026mdash;particularly fertility rates and sex ratios - have not been studied in regions like Amhara despite it being one of the most heavily impacted areas. To address this, the Birhan HDSS aims to provide updated demographic information by analyzing adult sex ratios and fertility rates within its study population, using existing surveillance data to offer valuable insights into the population structure and demographic conditions of the Amhara region in Ethiopia.\u003c/p\u003e\u003ch2\u003eObjective\u0026nbsp;\u003c/h2\u003e\n\u003cp\u003eTo evaluate the Adult Sex Ratio and key fertility indicators within the Birhan HDSS site in the Amhara region of Ethiopia from Dec 1, 2021, to Nov 30, 2022.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eThe Birhan Field site was established in June 2018 through a collaboration between Saint Paul's Hospital Millennium Medical College (SPHMMC) and Harvard School of Public Health (HSPH) in the North Shewa Zone of the Amhara Region, Ethiopia. The study area includes a health and demographic surveillance system (HDSS), which includes fourteen rural and two urban kebeles (the smallest administrative units used in Ethiopia) \u003cb\u003e(Figure: 1)\u003c/b\u003e. The primary objectives of this surveillance system are to ensure continuous and ongoing monitoring of the health and demographic conditions of the population in the area and to serve as a valuable resource as it provides a well-defined population sampling frame to conduct nested studies.\u003c/p\u003e \u003cp\u003eThe primary activity of the Birhan Health and Demographic Surveillance System (HDSS) consists of systematically conducting house-to-house visits within the surveillance area at regular three-month intervals. These visits are designed to actively monitor and update detailed information on both individual members and household-level dynamics, including births, deaths, migrations, marital status changes, and other demographic events.\u003c/p\u003e \u003cp\u003eIf new households have been established within the village - either through immigration or household formation - these households are identified, and comprehensive baseline data are collected. Once baseline information is gathered, these households are formally enrolled in the HDSS and become part of the ongoing surveillance system. In addition to capturing routine demographic events, the HDSS data collectors play a critical role in the early identification of pregnancies within the community. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe study team developed a Tangerine-based electronic data system for longitudinal data collection to support this process. This system operates in two ways: when syncing, the Tangerine Collect app allows data collectors to both upload (push) and download (pull) data from the Tangerine Aggregate central database. Data collected on tablets is regularly uploaded to the central database, and updates from the database are downloaded to the tablets whenever data collectors sync them, typically daily.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eWithin the HDSS population, there was a nested pregnancy and birth Birhan open cohort study, to estimate the causes of children and maternal mortality and morbidity. In this study, Women of reproductive age are regularly monitored for pregnancy screening by the cohort and HDSS data collectors, community key informants at the household level, and healthcare providers at health facilities within the catchment area. The woman is referred to the Birhan open cohort study team if a pregnancy is detected. Pregnant women who consented were enrolled and followed through antenatal, birth, and two years post-partum, conducting scheduled visits to assess their health and well-being throughout pregnancy, delivery, and the postnatal period.\u003c/p\u003e \u003cp\u003eThe central database served as a bridge for the HDSS and nested studies; updates made on each study participant were displayed for Birhan open cohort data collectors on a daily basis. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eWe extracted one year data (December 1, 2021, to November 30, 2022) from the HDSS and the Birhan Cohort. From the HDSS, we collected information on the average population of the study area during the study year and the number of women of reproductive age. Furthermore, we obtained the number of live births from the HDSS and the morbidity and mortality cohort datasets.\u003c/p\u003e \u003cp\u003eWith this data, we calculated key indicators related to fertility rates and ASR. The CBR represents the number of live births per 1,000 population. The GFR measures the number of live births per 1,000 women of reproductive age. The TFR estimates the average number of children a woman would have in her lifetime based on current birth rates. In addition to fertility indicators, we also calculated the ASR. The adult sex ratio represents the ratio of males to females in the adult population (15\u0026ndash;49 years old).\u003c/p\u003e \u003cp\u003eOur analytical strategies for measuring human fertility and ASR in the study area are based on descriptive statistics and involve the use of the following methods:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eCrude Birth Rate (CBR): The CBR is calculated by dividing the total number of live births recorded in a population over a year by the mid-year population and then multiplying by 1,000. CBR = (Total number of children born in a year) / (Mid-year Population) x 1000.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe GFR is calculated by dividing the total number of births per year by the female population in the reproductive age group and multiplying by 1,000. GFR = (Total number of children born in a year) / (Female Population, ages 15\u0026ndash;49) x 1000.[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe TFR measures the average number of children each woman would have over her reproductive age if the age-specific birth rates remain constant. It is calculated by summing the age-specific birth rates (ASFR) for each age group (e.g., 15\u0026ndash;19, 20\u0026ndash;24, 25\u0026ndash;29, \u0026hellip; 45\u0026ndash;49) and multiplying by 5. TFR\u0026thinsp;=\u0026thinsp;5 * \u0026sum;(ASFR).[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe ASR is calculated by dividing the number of adult males (15\u0026ndash;49 years old) by the number of adult females (15\u0026ndash;49 years old) and multiplying by 100.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e We obtained protocol approvals for both the HDSS and open cohort studies from the Institutional Review Boards (IRB) of Saint Paul's Hospital Millennium Medical College (SPHMMC) and Harvard T.H. Chan School of Public Health (HSPH). All methods were carried out in accordance with these approved protocols.\u003c/p\u003e \u003cp\u003eResult\u003c/p\u003e \u003cp\u003eThe Birhan Health and Demographic Surveillance System (HDSS) findings for the study period (December 1, 2021 \u0026ndash; November 30, 2022) provide valuable insights into the population structure. The mid-year population was 72,776, with more males (38,454) than females (34,322). The population pyramid reflects a predominantly young population, characterized by a broad base representing a large proportion of children and adolescents. Population numbers decline with increasing age, a pattern typical in developing regions.\u003c/p\u003e \u003cp\u003eNotably, the population pyramid highlights a skewed sex ratio favoring males in the 15\u0026ndash;25-year age group (\u003cb\u003eFigure: 2\u003c/b\u003e). Specifically, women made up 37.4% of the 15\u0026ndash;24-year age group, resulting in a sex ratio of 167.4 males for every 100 females. Across the broader reproductive age group (15\u0026ndash;50 years), the sex ratio was 125 males per 100 females. Overall, the study area exhibited a male-dominant population, with 112 males for every 100 females (\u003cb\u003eTable: 1\u003c/b\u003e)\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTable\u0026nbsp;1: Sex Ratio in Birhan HDSS Study Population in Amhara Region, Ethiopia,\u0026nbsp;2022\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"1\" nameend=\"c6\" namest=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eMale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003eFemale\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003eSex Ratio\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13,900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13,203\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e51.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u0026ndash;20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4,880\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,711\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e64.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u0026ndash;25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3,633\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,384\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u0026ndash;30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,796\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,805\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e49.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026ndash;35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,468\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,652\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e48.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u0026ndash;40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,189\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2,333\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e48.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u0026ndash;45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2,106\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1,725\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e55.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e45\u0026ndash;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1,394\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e944\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e59.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u0026gt;\u0026thinsp;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5,088\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5565\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e47.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u0026ndash;50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e19,466\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e15,554\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e\u003cb\u003e55.6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38,454\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e34,322\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c6\" namest=\"c4\"\u003e \u003cp\u003e52.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe population of women of reproductive age (WRA) in the study area totaled 14,086, among whom 1,476 live births occurred, comprising 748 boys and 728 girls. This results in a sex ratio at birth of 102.7 boys for every 100 girls, which is consistent with natural sex ratio patterns observed globally.\u003c/p\u003e \u003cp\u003eFertility rates were highest among women aged 20 to 34 years, reflecting both biological factors and prevailing social norms regarding childbearing. Specifically, women in the 25\u0026ndash;29 age group had the highest number of live births (424), followed closely by those aged 30\u0026ndash;34 years (399) and 20\u0026ndash;24 years (322). Fertility declined substantially after age 35, with markedly lower rates among women aged 40\u0026ndash;49 years.\u003c/p\u003e \u003cp\u003eCompared to national trends, the fertility rate in the Birhan HDSS population has declined. The Total Fertility Rate (TFR) for 2022 was 3.44 children per woman, lower than Ethiopia\u0026rsquo;s national TFR of 4.6 in 2016 and significantly lower than the 6.4 recorded in 1990. The decline in fertility is also evident across all age-specific fertility rates (ASFRs), with adolescent fertility (ages 15\u0026ndash;19) notably lower in Birhan HDSS (22 per 1,000 women) compared to the national rates reported in previous Ethiopian Demographic and Health Surveys (EDHS) (\u003cb\u003eTable: 2 \u0026amp; Figure: 3\u003c/b\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003eTable\u0026nbsp;2: Trends in Fertility Rates\u003c/span\u003e\u003c/p\u003e \u003cp\u003eTrends in ASFRs (per 1000 women) and TFRs in Ethiopia from 2000\u0026ndash;2016 and in Birhan HDSS in Amhara Region, Ethiopia,\u0026nbsp;2022\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c9\" namest=\"c8\"\u003e \u003cp\u003eBirhan HDSS study population\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge group\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNFFS 1990\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eEDHS 2000\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEDHS 2005\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEDHS 2011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eEDHS 2016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e2022\u003cb\u003e*\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003eWRA**\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003eLive births***\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15\u0026ndash;19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e110\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e104\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e80\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2276\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20\u0026ndash;24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e275\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e244\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e228\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e207\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e214\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e173\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1859\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e322\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e25\u0026ndash;29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e289\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e264\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e241\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e237\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e190\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2213\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e424\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e30\u0026ndash;34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e257\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e248\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e192\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e190\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e155\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2578\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e399\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e35\u0026ndash;39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e199\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e183\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e160\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e150\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e138\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2022\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e182\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e40\u0026ndash;44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e105\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e69\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1895\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e45\u0026ndash;49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e1244\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003e6.4\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cb\u003e5.900\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e5.5\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e4.8\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e4.6\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cb\u003e3.44\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e14086\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e\u003cb\u003e1476\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"9\" nameend=\"c9\" namest=\"c1\"\u003e \u003cp\u003e\u003cem\u003e*\u0026nbsp;Aage-specific and total fertility rates\u0026nbsp;in Brihan HDSS.\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e** Number of women of reproductive age in each age group Brihan HDSS.\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e*** Number of live births in each age group Brihan HDSS.\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe fertility analysis of the Birhan HDSS study population in 2022 reveals a decline in fertility indicators when compared to previous national averages. The Total Fertility Rate (TFR) was 3.44 children per woman, representing a 25.22% reduction from Ethiopia\u0026rsquo;s national TFR of 4.6, as reported in the 2016 Ethiopian Demographic and Health Survey (EDHS).\u003c/p\u003e \u003cp\u003eSimilarly, the Crude Birth Rate (CBR) in Birhan HDSS was 19.98 births per 1,000 population, which is 37.24% lower than the national average of 31.84 per 1,000 reported in 2016. The General Fertility Rate (GFR), which measures the number of live births per 1,000 women of reproductive age (15\u0026ndash;49 years), was also lower in Birhan, at 104.78, compared to the national figure of 156 in 2016. This represents a decrease of 32.83%.\u003c/p\u003e \u003cp\u003eThese reductions across key fertility indicators TFR, CBR, and GFR highlight an overall decline in fertility in the Birhan HDSS area relative to national trends observed over the past two decades (Table: 3 \u0026amp; Figure: 4).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCBR, GFR, and TFR in Ethiopia from 2000\u0026ndash;2016 and in Birhan HDSS Study Population in Amhara Region, Ethiopia,\u0026nbsp;2022\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFertility measures\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEHDS 2000*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eEDHS 2005*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEDHS 2011*\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eEDHS 2016**\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eBirhan HDSS 2022**\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eDifference\u003c/p\u003e \u003cp\u003e(** - *)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGFR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e193\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e179\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e161\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e156\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e104.784\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-32.83%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCBR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e41.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e35.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e34.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e31.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e19.984\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-37.24%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTFR\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.900\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e-25.22%\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"7\" nameend=\"c7\" namest=\"c1\"\u003e \u003cp\u003e* Fertility measures in Ethiopia EDHS\u003c/p\u003e \u003cp\u003e** Fertility measures of Birhan HDSS Study Population in Amhara Region, Ethiopia,\u0026nbsp;2022\u003c/p\u003e \u003cp\u003e** - * The difference in fertility measures between Ethiopia in EDHS 2016 and Birhan HDSS 2022\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussions","content":"\u003cp\u003eThe study, conducted in Birhan HDSS, Amhara region, Ethiopia, examined adult sex ratios and fertility rates. Among those aged 15\u0026ndash;24, women made up only 37.4%, with a sex ratio of 167.4 males per 100 females. For women aged 15\u0026ndash;50, the sex ratio was 125 males per 100 females. In 2022, the TFR was 3.44 children per woman, a 25.22% decline from Ethiopia\u0026rsquo;s national TFR of 4.6 in 2016. Other fertility indicators also dropped: the CBR was 19.98 per 1,000 population (down 37.24%), and GFR was 104.78 per 1,000 women of reproductive age (down 32.83%) compared to 2016 national figures[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe global average total fertility rate has declined over the years. In 1950-55, 1975-80, and 2005-10, the rates were 4.97, 3.86, and 2.5 children per woman, respectively. By 2021, it had further dropped to 2.32. [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] This fertility reduction caused the global population to decrease from 2% in the 1970s to 1.1% in 2017. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e] In East Africa, the pooled estimates indicate a total fertility rate of 4.74 children per woman [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], and the population growth rates reached their highest reported levels in 2017, at 2.7%. [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eTotal fertility rate dropping from 5.9 in 2000 to 4.6 in 2016. The Birhan HDSS population exhibited an even greater decline, with a TFR of 25.22% lower than the national average in 2016. This figure is comparable to the TFR of the Amhara region, which stood at 3.7 in 2016\u0026mdash;approximately 7% higher than Birhan\u0026rsquo;s\u0026mdash;indicating similar lifetime fertility levels. The Amhara region\u0026rsquo;s TFR decreased from 5.9 in 2000 to 3.7 in 2016, with intermediate values of 5.1 in 2005 and 4.2 in 2011. [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] National trends show a consistent reduction in fertility rates, and a 7% difference in TFR over six years aligns with these patterns.\u003c/p\u003e \u003cp\u003eAlthough the Ethiopian Demographic and Health Surveys (EDHS) do not provide Crude Birth Rate (CBR) and General Fertility Rate (GFR) data at the regional level, the observed reductions are significant, amounting to a 37.24% decrease in CBR and a 32.83% decrease in GFR since 2016. [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] This substantial decline highlights the importance of TFR as a robust measure of fertility, as it is the least affected by variations in the sex ratio. The total fertility rate reflects fertility behavior per woman rather than being influenced by the absolute number of women or men in the population[\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe migration of young women seems to be reducing the number of women of reproductive age in areas like Birhan HDSS. This trend is part of a broader urban transition in Ethiopia, where rural women often migrate abroad to earn money for future moves to towns. [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e] Higher sex ratios and lower birth rates are observed, partly due to fewer young women who typically have children earlier, with a median age at first birth of 18.7. This is because poorer women tend to give birth at younger ages [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], and with a median age at first birth of 18.7.[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e] Migration also impacts women's health; 29.2% of returnees from the Middle East experience common mental disorders. Additionally, migrants have lower conception rates during and after migration, influenced by temporary separation from partners and improved living conditions post-migration. [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Furthermore, migrants have a lower risk of conception during the migration period and often maintain lower conception rates than non-migrants in the long run. This could be due to the improvement in living standards experienced by migrants after settling in urban areas and the temporary separation from spouses.[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eStrengths of the study\u003c/strong\u003e \u003cp\u003eThe Birhan HDSS examined pregnancies and recorded birth outcomes for women of reproductive age four times during the study year. Community health workers also screened pregnancies in villages. A separate study team closely monitored pregnant women throughout childbirth, documenting birth outcomes at both the household and facility levels. This comprehensive approach to pregnancy screening and birth outcome registration offers greater value than surveys.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eLimitation of the study\u003c/strong\u003e \u003cp\u003eThe study didn\u0026rsquo;t quantify the exact migration figure over the study period in the study area, and this is our recommendation for future research.\u003c/p\u003e \u003c/p\u003e "},{"header":"Conclusion","content":"\u003cp\u003eThe findings reveal a young population with a higher male-to-female ratio, especially in younger age groups. Fertility rates are significantly lower than national averages, likely due to gendered migration and reduced conception risks among migrants linked to better living conditions in urban areas and temporary separation from partners. A key strength of the study is its thorough pregnancy screening and birth outcome tracking, offering more accurate data than traditional surveys. Monitoring these trends is essential for informed demographic planning and policymaking to support sustainable development.\u003c/p\u003e "},{"header":"Abbreviations","content":"\u003cp\u003eASFR: Age-Specific Birth Rates, ASR: \u0026nbsp;Adult Sex Ratio, BSc: Bachelor of Science, CBR: Crude Birth Rate, EDHS: Ethiopian Health and Demographic Surveys, GFR: General Fertility Rate, HDSS: Health and Demographic Surveillance System, HSPH: Harvard T.H. Chan School of Public Health, IRB: Institutional Review Board, MD: Medical Doctor, MPH: Master of Public Health, MSc: Master of Science, PhD: Doctor of Philosophy, National Family and Fertility Survey (NFFS), SPHMMC: Saint. Paul\u0026rsquo;s, Hospital Millennium Medical College, TFR: Total Fertility Rate, USA: United States of America.\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eEthics approval and consent to participate\u003c/h2\u003e\n\u003cp\u003eThe Institutional Review Board (IRB) of SPHMMC and HSPH granted ethical clearance, and verbal consent was secured from all respondents.\u003c/p\u003e\n\u003ch2\u003eConsent for Publication\u003c/h2\u003e\n\u003cp\u003eAll study participants gave informed consent, confirming their willingness to contribute to the research findings.\u003c/p\u003e\n\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e\n\u003cp\u003eThe datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003ch2\u003eCompeting interests\u003c/h2\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThis work has been supported by the Bill \u0026amp; Melinda Gates Foundation (grants INV-010382, INV-003612, and INV-006752) through the HaSET Maternal and Child Health Research Program.\u0026nbsp;\u003c/p\u003e\n\u003ch2\u003eAuthors' Contributions\u003c/h2\u003e\n\u003cp\u003eCB prepared the study materials, monitored the data collection process, contributed to data analysis, and drafted the manuscript. DB, CD, KA, and BM participated in preparing study materials, data collection, and manuscript development. FA and YM designed an electronic data collection system, oversaw the data collection process, analyzed the data, and contributed to the manuscript. GC supervised and approved the study materials, analysis plan, and final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgments\u003c/h2\u003e\n\u003cp\u003eWe acknowledge the kind help and encouragement we received from the study facilities. Our deepest gratitude goes to the women and healthcare providers who participated in this study and to all data collectors and supervisors for their dedicated work.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eWorld sex. ratio 2023 - StatisticsTimes.com. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://statisticstimes.com/demographics/world-sex-ratio.php\u003c/span\u003e\u003cspan address=\"https://statisticstimes.com/demographics/world-sex-ratio.php\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGender Ratio - Our World in Data. 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PMID: 7973839.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"The Total Fertility Rate, Crude Birth Rate, General Fertility Rate, and Adult Sex Ratio","lastPublishedDoi":"10.21203/rs.3.rs-5559868/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5559868/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction:\u003c/strong\u003e The study examined the adult sex ratio and fertility rate at Birhan Health and Demographic Surveillance System (HDSS) in the Amhara region of Ethiopia. Globally, the sex ratio at birth and total population remains stable, with approximately 105.6 boys born for every 100 girls and 101 males for every 100 females, respectively. Ethiopia's average population sex ratio is 101 males to 100 females. Fertility rates have declined globally since 1950, including in the Middle East, North Africa, and sub-Saharan Africa. Ethiopia's fertility rate decreased from 6.4 in 1990 to 4.6 in 2016.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethod:\u003c/strong\u003e The HDSS covers rural and urban areas, monitoring health and demographic conditions to provide an updated sampling frame for nested studies. Additionally, an open cohort study focused on maternal and under-two-year-old children's mortality and morbidity was conducted. Data from both the HDSS and the open cohort study were used to calculate key indicators, including Crude Birth Rate (CBR), General Fertility Rate (GFR), Total Fertility Rate (TFR), and Adult Sex Ratio (ASR). The study's strength lies in its comprehensive approach to pregnancy screening and birth outcome registration, yielding valuable data beyond traditional surveys.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResult:\u003c/strong\u003e The mid-year population was 72,776, with a higher number of males (38,454) than females (34,322). Among individuals aged 15–24 years, women made up 37.4% of the group, resulting in a sex ratio of 167.4 males per 100 females. For the broader reproductive age range (15–50 years), the sex ratio stood at 125 males per 100 females. In 2022, the TFR was 3.44 children per woman, reflecting a 25.22% decline compared to Ethiopia's national TFR of 4.6 in 2016. Other key fertility indicators also demonstrated notable reductions: the CBR was 19.98 per 1,000 population, and the GFR was 104.78 per 1,000 women of reproductive age, marking decreases of 37.24% and 32.83%, respectively, from the 2016 national averages.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e The findings highlight a youthful population with a higher male-to-female ratio, particularly among younger age groups. Fertility rates are notably lower compared to national figures. The lower fertility rate observed in these circumstances can be attributed to gendered migration patterns and the potential decrease in the risk of conception among migrants, stemming from improved living standards in urban areas and temporary separation from spouses.\u003c/p\u003e","manuscriptTitle":"Adult Sex Ratio and Local Birth Rates in Birhan Field Site, Amhara Region, Ethiopia","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-14 22:58:09","doi":"10.21203/rs.3.rs-5559868/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-04-25T19:16:34+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-24T08:20:14+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-04-14T17:06:13+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"246782374389649772268993707288087705740","date":"2025-04-14T17:04:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"146461072902234226124656361444012441719","date":"2025-04-14T06:05:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-04-09T12:52:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-04-02T08:22:18+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-03-23T19:26:02+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e93df462-4d9e-4904-9c98-b87b0a9a36d1","owner":[],"postedDate":"April 14th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":46914816,"name":"Health sciences/Health care"},{"id":46914817,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2025-10-27T16:28:48+00:00","versionOfRecord":{"articleIdentity":"rs-5559868","link":"https://doi.org/10.1038/s41598-025-20750-y","journal":{"identity":"scientific-reports","isVorOnly":false,"title":"Scientific Reports"},"publishedOn":"2025-10-22 16:17:27","publishedOnDateReadable":"October 22nd, 2025"},"versionCreatedAt":"2025-04-14 22:58:09","video":"","vorDoi":"10.1038/s41598-025-20750-y","vorDoiUrl":"https://doi.org/10.1038/s41598-025-20750-y","workflowStages":[]},"version":"v1","identity":"rs-5559868","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5559868","identity":"rs-5559868","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}