Exposure of Ambient PM2.5 During Gametogenesis Period Affects the Birth Outcome: Results from the Project ELEFANT.

Various environmental and behavioural factors influence neonatal health. Gamete formation (gametogenesis) is a crucial period which affects embryo development and neonatal health and ambient air pollution exposure at this stage may lead to an adverse birth outcome. Previous epidemiological and toxicological research demonstrated a strong association between maternal ambient air pollution exposure and adverse birth outcomes. However, the joint exposure-outcome of paternal exposure (76 days before the last menstruation and 14 days after the last menstruation) and maternal exposure (14 days after the last menstruation) when exploring the mechanism of the influence of air pollutants on pregnancy outcome and neonatal health remains unexplored. Here, in the Project Environmental and LifEstyle FActors iN metabolic health throughout life-course Trajectories (ELEFANT), we collected the data of 10,960 singleton pregnant women with 24-42 completed gestational weeks and included them in this study. A multinominal logistic regression model was applied to investigate the association between adverse birth outcomes and ambient PM2.5 exposure levels during spermatogenesis and oogenesis. Results from the binary classification of ambient PM2.5 exposure showed that the risk of abnormal birthweight was significantly greater when ambient PM2.5 exposure was both higher during spermatogenesis and oogenesis, with RRs of 1.86 (95% CI: 1.02, 3.39). The risk of macrosomia (RR: 1.88 (95% CI: 1.13, 3.12)) increased significantly when ambient PM2.5 levels were higher during spermatogenesis. Primiparity and primigravity are more likely to be influenced by higher ambient PM2.5 levels during spermatogenesis. In conclusion, more attention should be paid to higher exposure level of ambient PM2.5 during spermatogenesis.