Associations between ambient temperature and pregnancy outcomes from three south Asian sites of the Global Network Maternal Newborn Health Registry: A retrospective cohort study

Objective Growing evidence suggests that environmental heat stress negatively influences fetal growth and pregnancy outcomes. However, few studies have examined the impact of heat stress on pregnancy outcomes in low‐resource settings. We combined data from a large multi‐country maternal–child health registry and meteorological data to assess the impacts of heat stress. Design Retrospective cohort study. Setting Three sites based in south Asia as part of the Global Network for Women's and Children's Health research in India (Belagavi and Nagpur) and Pakistan (Thatta). Population or Sample Data from women enrolled between 2014 and 2020 in the Global Network's Maternal Newborn Health Registry (MNHR), a prospective, population‐based registry of pregnancies, were used. Methods A total of 126 273 pregnant women were included in this analysis. Daily maximal air temperatures (Tmax) were acquired from local meteorological records. Associations between averages of daily maximal temperatures for each trimester and main outcomes were analysed using a modified Poisson regression approach. Main outcomes measures Incidence of stillbirth, preterm birth, low birthweight (