Maternal lead exposure and preeclampsia risk in sub-Saharan Africa: a comparative risk assessment

Background: Preeclampsia is a leading cause of maternal morbidity and mortality in sub Saharan Africa. Lead exposure remains widespread across the region, yet its contribution to preeclampsia risk has not been quantified at the population level. The World Health Organization (WHO, 2025) estimated that in 2023, there were approximately 182,000 maternal deaths in SSA (70 % of global deaths), and that approximately 16% of these deaths were due to hypertensive disorders of pregnancy (HDP) (Say et al, 2014). This implies that there were approximately 29,000 HDP related maternal deaths annually in the SSA (with preeclampsia/eclampsia constituting a substantial fraction). Methods: We synthesized maternal blood lead level (BLL) data from pregnancy biomonitoring studies conducted in sub-Saharan Africa and supplemented these with soil derived exposure scenarios representing severely contaminated settings. Using published meta analytic evidence indicating a 1.6% increase in the odds of preeclampsia per 1 microgram/dL increase in maternal BLL, we modelled relative odds and predicted absolute preeclampsia risk under a range of plausible baseline prevalence assumptions. Sensitivity analyses examined uncertainty related to exposure extrapolation and baseline preeclampsia prevalence, and population attributable fractions were estimated across baseline scenarios. Results: Biomonitoring derived maternal BLLs were associated with modest but consistent increases in predicted preeclampsia risk across baseline scenarios. Soil derived exposure scenarios representing severe environmental contamination yielded sharply increasing predicted risks under uncapped extrapolation. Sensitivity analyses demonstrated that relative exposure response gradients were robust to modelling assumptions, while absolute risk and attributable burden estimates varied with baseline prevalence. The mean maternal blood lead level from fifteen (15) separate studies in SSA was 26.24 microgram/dL (Range: 0.83 to 99 microgram/dL) (Bede et al., 2016) while the mean or geometric mean BLL in of women the United States, Canada, Germany, South Korea, China, and Mexico were between 0.5 and 2.4 microgram/dL. Conclusion: Maternal lead exposure may contribute meaningfully to preeclampsia risk in sub Saharan Africa, with modest effects at commonly observed exposure levels and potentially substantial effects in severely contaminated settings. These findings support the inclusion of environmental lead exposure prevention within broader maternal health strategies.