Prenatal exposure to flood and risk of low birth weight: a multi-country study from 36 African countries

Climate change is increasing the frequency, duration, and severity of floods escalating worldwide, exposing pregnant women to growing health risks. While previous literature has demonstrated an association between prenatal flood exposure and low birth weight (LBW) in offspring, evidence in low- and middle-income countries (LMICs) remains limited. In this cross-sectional study, birth records from the Demographic and Health Surveys (DHS) were geospatially matched with flood data from the Dartmouth Flood Observatory (DFO). A total of 290,008 singleton live births across 36 African LMICs were analyzed. Logistic regression models were employed to estimate odds ratios (ORs) for the association between prenatal flood exposure and LBW prevalence. The burden of LBW attributable to prenatal flood exposure was estimated across 28 of 36 African LMICs. We observed positive associations between prenatal flood exposure and LBW (OR: 1.076, 95% CI: 1.028 to 1.128), with the effect sizes escalating progressively across severity exposure levels (P for trend = 0.003). Higher odds ratios were found among urban residents, mothers of advanced maternal age (≥ 35 years), and households utilizing unsafe water or flush toilets. We estimated that prenatal flood exposure was associated with approximately 234 excess LBW cases per 1,000 births per decade, totaling 467,904 (95% CI: 180,434 to 751,720) over the 21-year study period (from 2000 to 2020) across 28 African LMICs. Our findings highlight the urgency of addressing health disparities stemming from prenatal floods and extreme environmental events for neonatal health promotion.