What has high fertility got to do with the low birth weight problem in Africa?

Background: There has been much concern about adverse individual and societal consequences of high fertility in sub-Saharan Africa. One concern is that children of high birth orders may have low birth weight. However, the evidence for such an effect is not strong. Objective: Our objective is to investigate whether a woman’s high parity status might increase her risks of having a baby with low birth weight. Methods: Pooling 60 Demographic and Health Surveys data-sets from 32 sub-Saharan countries, we selected children of mothers who had at least two births of order two or higher within the five years preceding the surveys. We modeled the probability of having a child with low birth weight and controlled for all mother-specific, household, or community characteristics that are constant over the period of analysis, by including fixed-effects for the mother. We also controlled for salient factors including sex, maternal age, preceding birth interval, and whether prenatal care was received. Results: We found no adverse effect of increasing parity on the odds of having a child with low birth weight at normative ranges; such effects only manifest at extremely high parities - nine or more children. At moderately high parities, the chance of low birth weight is actually lower than at very low parities. Conclusions: While high fertility may lead to various adverse outcomes for African families, low birth weight appears not to be among these outcomes. Other factors, such as adolescent childbearing, poverty, and inadequate prenatal care may be more important determinants of low birth weight in Africa.