Marriage and First Birth Intervals in Early and Late Marrying Societies: An Exploration of Determinants

Sajeda Amin, Population Council
Ashish Bajracharya, Population Council

This paper explores potential explanations for the varying lengths of first birth intervals observed between early- and late-marrying regimes in developing countries. We propose that underlying biological mechanisms related to the fecundity of girls at the time of marriage govern first birth intervals and shape the social norms surrounding childbearing. We use multi-country data from the Demographic Health Surveys and estimate multi-level models to explore both biological and social norm-related mechanisms that determine the timing of first birth in different marriage regimes. We hypothesize that longer birth intervals in early-marrying societies are a result of the sub-fecundity of girls when they enter unions. In late-marrying regimes, girls marry at their most fecund periods and are impatient to establish fertility, resulting in shorter birth intervals. Policy implications of these findings, which suggest distinct emphases in the promotion of contraception in different marriage regimes, are discussed.