Prenatal Exposure to Fine Particles, Premature Rupture of Membranes and Gestational Age: A Prospective Cohort Study

Abstract

Background: The association between maternal exposure to fine particulate matter (PM2.5) and gestational age remains unclear, components of fine particles have received little investigation. Few studies have focused on preconception exposure. Methods: A total of 1715 pregnant women were enrolled from 2014 to 2015 from hospitals affiliated with Nanjing Medical University. Personal exposure to PM2.5 has been calculated using satellite-based and chemical transport modelling products. Components of PM2.5 were also assessed. Delivery data were acquired from electronic medical records. Gestational age (days) was handled as a linear term to verify the association with PM2.5 and its components. We conducted mediation analysis to explore the role of PROM. Findings: A total of 1507(87·9%) participants were included in the final analysis. From 12 weeks before conception to the first trimester, the gestational age was reduced by 0·62 days (95% CI: -1·03, -0·20) per interquartile range (IQR) increase in PM2.5 exposure. After early exposure period was separated into two groups, each IQR increase in PM2.5 exposure would reduce the gestational age by 1·14 days (95% CI: -1·87, -0·40) in the 12 weeks before pregnancy. With maternal exposure to PM2.5 early in the first trimester, gestational age was reduced by 1·25 days (95% CI: -2·40, -0·10). After mediation analysis, we found PROM mediated the association between PM2.5 exposure and gestational age by 16·9% in the first trimester. Components analysis indicated that prenatal exposure to BC, OM, NO3- would increase the risk of PROM and result in decreased gestational age. Interpretation: Prenatal exposure to PM2.5 could increase the risk of decreased gestational age. PROM partially mediates this association. Additionally, we should pay more attention to the related components and exposure from preconception. Funding: National Key R&D Program of China, the National Natural Science Foundation of China, Medical Science and Technology Projects of Jiangsu Province, the Qing Lan Project of Jiangsu Province, and the Six Talent Peaks Project in Jiangsu Province. Declaration of Interest: All authors declare no competing interests. Ethical Approval: The study protocol was approved by the institutional review board of Nanjing Medical University and complied with the principles outlined in the Helsinki Declaration.