Analysis of factors associated with the number of children ever born to women in rural Ethiopia using truncated generalized Poisson model

Rapid population growth and high fertility rates in low-income countries adversely affect the provision of sexual and reproductive healthcare services. A high fertility rate has serious health implications for both the mother and the children she bears, and thus, investigating the factors behind this phenomenon is of paramount importance. The data for this study were extracted from the 2016 Ethiopia Demographic and Health Survey (EDHS 2016). The responsible variable, the number of children ever born (NCEB), was zero-truncated since only women who had at least one live birth at the time of the survey were considered. Data from a total of 6256 women residing in rural Ethiopia were analyzed using a zero-truncated generalized Poisson model which takes into account any type of dispersion and the truncated nature of the response variable simultaneously. Moreover, an exposure variable (specifically, cohabitation duration) was incorporated into the model to ensure comparability of subjects that are observed for different durations of time, and sensitivity analysis was conducted to validate its inclusion. Model selection criteria as well as sensitivity analysis revealed that the zero-truncated generalized Poisson model with exposure outperforms all other candidate count data models. Factors that were significantly associated with bearing more children include early age at first birth, child mortality, low economic status and women’s land ownership. On the other hand, contraceptive use, women’s education and media exposure had a negative impact on the NCEB per woman. The results also revealed significant regional variation. Specifically, women in Somali Region registered significantly higher NCEB than those in other regions. To curb high maternal fertility among rural women, interventions that target uneducated and poorest women; measures to combat early initiation of childbearing; unreserved efforts aimed at reducing child mortality; and promoting the use of birth control measures are recommended. Moreover, relevant bodies should enhance the provision of family planning (FP) and counselling services as well as the supply of FP commodities that selectively target regions with high child births (e.g., Somali Region). From the methodology aspect, shifting from the standard Poisson regression to an appropriate class of generalized Poisson models is also recommended.