Association between prenatal PM2.5 exposure and the risk of large for gestational age.

BACKGROUND: The relationship between particulate matter <2.5 µm (PM2.5) and large for gestational age (LGA) is unclear, and studies conducted in highly polluted areas are lacking. We aimed to explore the association between PM2.5 and the risk of LGA in China. METHODS: Maternal and neonatal characteristics were collected in the National Prepregnancy Examination Project. The definition of LGA was neonates with a weight over the 90th percentile for gestational age. Logistic regression was used to evaluate the relationship between PM2.5 exposure and the risk of LGA. The dose-response relationship was evaluated using a restricted cubic spline model. RESULTS: There were 196,243 mother-neonate pairs included, among which the percentage of LGA was 15.3%. The average PM2.5 concentration was 75.29 µg/m3. A 10 µg/m3 increase in PM2.5 during the whole pregnancy was associated with an increased risk of LGA (odds ratio (OR) 1.097, 95% confidence interval (CI) 1.091-1.103). Pregnant women in the high-exposure group had a higher risk of giving birth to an LGA infant (OR 1.37, 95% CI 1.33-1.41). There was a nonlinear relationship between PM2.5 concentration and the risk of LGA, and the risk increased more rapidly at higher PM2.5 levels. CONCLUSIONS: Prenatal exposure to PM2.5 was linked to an increased risk of LGA. IMPACT: A nation-wide study in a highly polluted country suggested the association between prenatal PM2.5 exposure and LGA. A trimester-specific relationship between PM2.5 exposure and LGA was established. Call for attention on the pregnant women in highly polluted areas who were in high risk of giving birth to LGA.