Despite the worldwide decrease in fertility rates, Sub-Saharan Africa is still an exception,
showing an almost non-declining trend over the past 50 years. High fertility rates may persist
where the risk of child mortality is relevant, pushing parents to opt for a larger number of
children. This paper tests this hypothesis by exploring the middle-run impact of a temporary
exogenous decrease in child mortality on household fertility in rural Nigeria caused by positive
exogenous weather shocks. The main results show that abundant rainfall decrease child
mortality, pushing households to decrease their fertility. Interacting the weather shocks
with the initial number of children shows that the larger the household is the larger the
fertility decrease is. Yet, for the average household with three children, I find that, despite a
25.8% decrease in child mortality, fertility still increases by 15.9% three years after the shock,
making the household bigger in size. Consistent with such partial adjustment, household food
security and children’s anthropometric measures deteriorate. This matches the predictions
of a theoretical framework proposed in the paper, which shows that the magnitude of the
fertility adjustment positively depends on the distance to the preferred fertility level and
the number of children alive at the moment of the shock. The empirical analysis tests this
prediction, solving the endogeneity of the number of children by using the gender of the
first-born as an instrumental variable.