Maternal exposure to Waste-to-Energy plants and risks of adverse birth outcomes and hypertensive pregnancy disorders in Lazio, Italy.

Evidence on the effects of waste incineration on adverse birth outcomes (ABO) and hypertensive disorders of pregnancy (HDP) is limited. We investigated the association between maternal exposure to a waste-to-energy (WTE) plant in Lazio Region and ABO/HDP. Employing a difference-in-differences (DiD) design, we assessed changes related to the plant's deactivation (2017), comparing outcomes to a control WTE plant that remained operational. Mothers with geocoded residential address within 7 km from Colleferro (exposed area) and San Vittore del Lazio (control area) plants who delivered between 2007 and 2023 were enrolled. Information was derived from regional health databases. Outcome-specific multivariate logistic models included interaction terms between a "pre-post" variable (0 for deliveries in the operational period - 1 for deliveries in the post-operational period) and a variable indicating the plant (Colleferro/San Vittore) linked to each delivery. Secondary analyses considered extended buffers around the plants or a control group from a broader area surrounding Colleferro, instead of San Vittore. 25,360 deliveries occurred within 7 km from the two WTE plants. After Colleferro plant's deactivation, pre-eclampsia risk decreased compared to San Vittore (OR = 0.35; 95 % CI: 0.13-0.93). Suggestions of association were noted for ABO, for example preterm birth (OR = 0.83; 95 % CI: 0.62-1.10). Pre-eclampsia risk remained low when using an extended buffer for the delivery selection. Exposure to WTE plant emissions was associated with ABO and HDP. While further research is needed, public health measures should enhance stricter emission monitoring, cleaner waste management, and prevention for pregnant women in affected areas.