Time to first birth and its predictors among reproductive age women in high fertility countries in Sub-Saharan Africa: Inverse Weibull gamma shared frailty model

BACKGROUND: Early initiation of childbearing leads to an increase in total fertility rate and population growth. It has been linked with both maternal and child morbidity and mortality. However, there is limited information on the timing of the first birth and its predictors in the area so far. Therefore, determining the time to first birth and its predictors will help to design strategies to improve fertility rate, maternal and child survival. METHODS: The survey used recent (2010 – 2018) Demographic and Health data; a stratified, two-stage cluster sampling technique was used to select the sample. Inverse Weibull gamma shared frailty model was used to model the data at 95% confidence interval. Adjusted hazard ratio (AHR) and median hazard ratio (MHR) were reported as effect size. Statistical significance was declared at p value < 0.05. RESULTS: The overall median age at first birth was found to be 19 years (IQR: 16, 21 years). Rural residency (AHR = 1.02, 95%, CI 1.00,1.04), agricultural employee (AHR = 1.14, 95%, CI 1.13, 1.17), and nonagricultural employee (AHR = 1.06, 95%, CI 1.05, 1.08), marriage below 15 years (AHR = 5.47, 95%, CI 5.37, 5.57) and 15–17 years (AHR = 3.27, 95%, CI 3.22, 3.32), had sex below 15 years (AHR = = 1.57, 95%, CI 1.54, 1.61) and 15–17 years (AHR = 1.38, 95%, CI 1.38, 1.43), women who had unmet need for contraceptive (AHR = 1.39, 95%, CI 1.37, 1.42), and met need (AHR = 1.32, 95%, CI 1.30, 1.35), high spousal age gap (AHR = 1.17, 95%, CI 1.15, 1.19), not heard family planning message (AHR = 1.02, 95%, CI 1.01,1.04) were the higher hazard of early childbirth. CONCLUSION: The median age at first birth was found to be 19 years. This is lower than the optimal age for giving first birth, which is between late 20 s and early 30 s years. Rural residences, occupation, hearing family planning massage in the media, early sexual intercourse, early age at first marriage, high spousal gap, and unmet need for family planning were predictors of first birth at an early age. Thus, governments and non-governmental organizations should strive to implement programs that aim to reduce early age at first birth by considering these factors.