Relationship Between Changing Malaria Burden and Low Birth Weight in Sub-Saharan Africa

According to the World Health Organization (WHO), in 2018, an estimated 228 million malaria cases occurred worldwide with most cases occurring in sub-Saharan Africa. Scale up of vector control tools coupled with increased access to diagnosis and effective treatment has resulted in a large decline in malaria prevalence in some areas, but other areas have seen little change. Although interventional studies demonstrate that preventing malaria during pregnancy can reduce the low birth weight (i.e., child's birth weight $<$ 2,500 grams) rate, it remains unknown whether natural changes in parasite transmission and malaria burden can improve birth outcomes. In this work, we conducted an observational study of the effect of changing malaria burden on low birth weight using data from 18,112 births in 19 countries in sub-Saharan African countries. A malaria prevalence decline from a high rate (Plasmodium falciparum parasite rate in children aged 2-up-to-10 (i.e., $PfPR_{2-10}$) $>$0.4) to a low rate ($PfPR_{2-10}$ $<$0.2) is estimated to reduce the rate of low birth weight by 1.48 percentage point (95% confidence interval: 3.70 percentage point reduction, 0.74 percentage point increase), which is a 17% reduction in the low birth weight rate compared to the average (8.6%) in our study population with observed birth weight records (1.48/8.6 $\approx$ 17%). When focusing on first pregnancies, a malaria prevalence decline from a high rate to a low rate is estimated to reduce the low birth weight rate by more than for all births, 3.73 percentage point (95% confidence interval: 9.11 percentage point reduction, 1.64 percentage point increase).