Evaluating the association between household water, sanitation and hygiene (WASH) and selected placenta-related complications in The Gambia, Kenya and Mozambique

Placenta-related complications contribute substantially to maternal and perinatal mortality globally, with the greatest burden in low- and middle-income countries (LMICs). However, the potential influence of inadequate household water, sanitation and hygiene (WASH) on these outcomes remains poorly characterised. We investigated associations between household WASH conditions and selected placenta-related complications, including pre-eclampsia, small-for-gestational-age (SGA) and stillbirth, in The Gambia, Kenya and Mozambique. This secondary analysis was nested within PRECISE (PREgnancy Care Integrating Translational Science, Everywhere), a prospective observational cohort of 5,745 unselected pregnant women. Multivariable modified Poisson regression with robust standard errors was used to assess associations between household WASH exposures and pre-eclampsia, SGA or stillbirth. Missing exposure and covariate data were low (<5%) and handled using multiple imputation. Compared with water piped into the dwelling or plot, other improved water sources (adjusted relative risk [aRR] 1.18, 95% confidence interval [CI] 1.07-1.31, p = 0.002) and unimproved water sources (aRR 1.23, 95% CI 1.00-1.50, p = 0.049) were associated with a higher risk of any selected placenta-related complication. Unimproved sanitation facilities, compared with improved facilities, were also associated with increased risk (aRR 1.15, 95% CI 1.02-1.30, p = 0.019). The findings suggest that household‑level WASH conditions may be associated with selected placenta‑related complications through both direct and indirect pathways. Water sources, whether unimproved or improved, may be contaminated, and collection, transport, and storage further increase contamination risks while adding a physical burden to water collectors. Unsafe sanitation may also increase exposure to enteric pathogens. Given the observed associations, targeted WASH interventions warrant investigation as a potential strategy to reduce placenta-related complications and improve maternal and neonatal health outcomes in LMICs. Future research should explore the mechanisms linking WASH to pre-eclampsia, SGA, stillbirth and other placenta-related complications, and assess the effect of comprehensive WASH interventions.