Polygyny and the Number of Children Ever Born in Afghanistan: The Moderating Role of Education—A Cross-Sectional Study

Objective: This study aims to investigate the relationship between polygyny and the number of children ever born (CEB), as well as the moderating effects of education on this relationship in the context of Afghanistan. Additionally, decomposition analysis of the marginal effect will be utilized to identify the factors that influence the likelihood of having a certain number of children. Methods: A zero-inflated negative binomial (ZINB) regression model and marginal effect analysis were applied to the 2015 Afghanistan Demographic and Health Survey (AfDHS) with a sample (n = 29 461 women aged 15–49). CEB measured the number of children born to each woman; polygyny was assessed based on whether women were in polygynous or monogamous unions. All analyses were performed using STATA version 18.1. Results: About 7% of the sample were in polygynous marriages, and the average number of children ever born (CEB) was 4.18. The ZINB model indicates that polygynous women had a 12% lower likelihood of higher CEB; when education was included as a moderator, this reduction increased to 13%. The marginal effects further show that polygynous women had, on average, 0.54 fewer children than monogamous women. Education also demonstrated a protective effect: primary education was associated with 0.17 fewer children, while higher education reduced the number of children by 0.58. Conclusion: This study indicates that decreases in CEB among women in both polygynous and monogamous unions are linked to higher levels of women's education and delayed marriage. The study concludes that increasing access to family planning and promoting women's education may reduce the disparities in CEB between polygyny and monogamy in Afghanistan.