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

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.