Birth month is predictive of early life outcomes in sub-Saharan Africa

Under-five mortality rates (U5MR) have been declining slowly in Sub-Saharan Africa: between 1990 and 2008 the U5MR declined by only 22%. If there is a strong relationship between birth month and U5MR, then policies that help women conceive during optimal periods or that improve the health of pregnant women may help reduce U5MR. But the effectiveness of such policies will depend on whether the birth month effects are the result of structural differences in fertility patterns, or due to differences in pre and post-natal environments.
We use piecewise exponential hazard models to analyze the relationship between birth month and U5MR, in 30 SSA countries using data from the Demographic and Health Surveys. We also use logistic regression models to analyze the relationship between birth month and stunting.
The birth month effects on child mortality and stunting are large and statistically significant. On average, the U5MR associated with the birth month with the highest cumulative hazard is 39% higher than the U5MR for the birth month with lowest cumulative hazard. The maximum difference in predicted probabilities of being stunted between two birth months is on average nine percentage points. The birth month effects are not due to social-demographic differences in fertility patterns.