Prenatal air pollution exposure and postpartum glucose intolerance in women with gestational diabetes mellitus: Identifying susceptible windows.

Prenatal air pollution has been linked to gestational diabetes mellitus (GDM), but its persistent impacts on postpartum glucose intolerance (PGI) in women with GDM remain uncertain. In this study, we aimed to explore the relationships of prenatal air pollution with PGI and glucose levels in women with GDM and identify potential susceptible windows. This retrospective cohort study involved 7046 women with GDM delivering at the Guangdong Women and Children Hospital (2015-2022). Air pollution (PM2.5, PM10, NO2, CO, SO2, and O3) levels were estimated using the ChinaHighAirPollutants dataset. PGI was diagnosed at 4-12 weeks postpartum with a 75 g oral glucose tolerance test. Modified Poisson regression, linear regression, and distributed lag models were employed to explore the relationships of prenatal air pollution with PGI and postpartum glucose levels. Among the 7046 GDM women, 2226 (31.6 %) developed PGI. Prenatal exposure to multiple air pollutants was related to a higher PGI risk and elevated postpartum OGTT 2-h glucose levels. The second trimester was identified as the primary susceptible window for PGI, where per 10 μg/m3 increment in PM2.5 (relative risk [RR]: 1.09, 95 % confidence interval [CI]: 1.02, 1.17), PM10 (RR: 1.07, 95 % CI: 1.03, 1.12), and NO2 (RR: 1.08, 95 % CI: 1.03, 1.14), and per 100 μg/m3 increment in CO (RR: 1.06, 95 % CI: 1.01, 1.11) were linked to higher PGI risk. These findings highlight the need for targeted air pollution reduction measures in this high-risk population to mitigate diabetes progression.