Effects of Birth Month on Child Health and Survival in Sub-Saharan Africa.

Birth month is broadly predictive of both under-5 mortality rates and stunting throughout most of sub-Saharan Africa (SSA). Observed factors, such as mother's age at birth and educational status, are correlated with birth month but are not the main factors underlying the relationship between birth month and child health. Accounting for maternal selection via a fixed-effects model attenuates the relationship between birth month and health in many SSA countries. In the remaining countries, the effect of birth month may be mediated by environmental factors. This study found that birth month effects on mortality typically do not vary across age intervals; the differential mortality rates by birth month are evident in the neonatal period and continue across age intervals. The male-to-female sex ratio at birth did not vary by birth month, which suggests that in utero exposures are not influencing fetal loss, and that therefore the birth month effects are not likely a result of selective survival during the in utero period. In one-third of the sample, the birth month effects on stunting diminished after the age of 2 years; therefore, some children were able to catch up. Policies to improve child health should target pregnant women and infants and must take seasonality into account.