Maternal exposure to ozone and risk of gestational hypertension and eclampsia in the United States

Background: Exposure to ambient ozone during pregnancy may be linked with hypertensive disorders in pregnancy, but evidence is largely unknown. We aimed to estimate the association between maternal exposure to ozone and risk of gestational hypertension and eclampsia in the contiguous United States (US). Methods: We included 2,393,346 normotensive mothers aged from 18 to 50 years old who had a live singleton birth documented in the National Vital Statistics system in the US in 2002. We obtained information on gestational hyper-tension and eclampsia from birth certificates. We estimated daily ozone concentrations from a spatiotemporal ensem-ble model. We used distributed lag model and logistic regression to estimate the association between monthly ozone exposure and risk of gestational hypertension or eclampsia after adjusting for individual-level covariates and county poverty rate. Results: Of the 2,393,346 pregnant women, there were 79,174 women with gestational hypertension and 6034 with eclampsia. A 10 parts per billion (ppb) increase in ozone was associated with an increased risk of gestational hyperten-sion over 1-3 months before conception (OR = 1.042, 95 % CI: 1.029, 1.056), 2-3 months after conception (OR = 1.058, 95 % CI: 1.040, 1.077), and 3-5 months after conception (OR = 1.031, 95 % CI: 1.018, 1.044). The corresponding OR for eclampsia was 1.115 (95 % CI: 1.074, 1.158), 1.048 (95 % CI: 1.020, 1.077), and 1.070 (95 % CI: 1.032, 1.110), respectively. Conclusions: Exposure to ozone was associated with an increased risk of gestational hypertension or eclampsia, especially during 2 to 4 months after conception.

Automated summary

A study found that exposure to ambient ozone during pregnancy may be associated with hypertensive disorders in pregnancy. The research in the contiguous United States linked maternal exposure to ozone with the risk of gestational hypertension and eclampsia, showing a significant association. This has important implications for women's health and pregnancy management.