Association between maternal exposure to air pollution and intrapartum fetal distress: A retrospective cohort study.

This study aimed to investigate the association between maternal exposure to ambient air pollution and intrapartum fetal distress. The retrospective data were obtained for 150 parturients, ages 19-45, referred to Kamali Teaching Hospital, Karaj, Iran, in 2016. To assess the impact of the 2, 4, and 8 weeks exposure windows before the delivery of particulate matter ≤ 10 micrometers (PM10) and sulfur dioxide (SO2) on fetal distress incidence, logistic regression models were fitted, crudely and adjusted for maternal covariates. The parturients' ages owned a mean (standard deviation) of 30.4 (5.4). Moreover, 17 fetal distress cases were detected (11.3 %), demonstrating higher proportions of cousin marriage and family history of diabetes than the non-fetal distress group. Adjusted for body mass index, cousin marriage, abortion, and family history of diabetes, and over the eight weeks exposure window, a five µg/m3 increase of SO2 and PM10 provided odds ratios of 2.12 (95 % CI: 1.04-4.30) and 1.61 (95 % CI: 1.08-2.40), respectively, for fetal distress incidence. To conclude, we found the long-term impacts of SO2 and PM10 on the incidence of fetal distress based on the exposure level during the last eight weeks of pregnancy.