Effects of particulate matter exposure during pregnancy on birth weight: A retrospective cohort study in Suzhou, China

Abstract

Background: Recent studies have identified that exposure to particulate matter during pregnancy could result in adverse birth outcomes, but the effects of exposure at trimester-specific intervals are inconsistent.

Objective: Our primary goal was to investigate whether particulate matter exposure during pregnancy could affect birth weight and gestational age of neonates.

Methods: A retrospective cohort study was conducted to examine the relationship between maternal particulate matter exposure and neonatal birth weight. We collected 14,455 births records linked to hospital admission records (delivery and antenatal) from January 2013 to December 2015 in Suzhou Municipal Hospital. Air monitoring data in the same timeframe were also collected from Suzhou Environmental Protection Agency. The risk of low birth weight due to the exposure to PM_2.5 (with median aerodynamic diameter≤2.5μm) and PM₁₀ (with median aerodynamic diameter≤10μm) at each trimester and throughout the entire pregnancy were assessed. Linear regression models were applied and potential confounding factors were adjusted for data analysis. Gestational age, which was another important birth outcome, and its association with maternal particulate matter exposure were also studied.

Results: The final analysis included 10,915 singleton live births. Using multiple linear regression models, we found that gestational exposure to PM_2.5 and PM₁₀ at 10μg/m³ increments in the second trimester led to decreases in birth weight of 4.94g (95% confidence interval: -9.828, -0.046) and 5.65g (95% confidence interval: -10.110, -1.188), respectively. However, gestational age was not significantly associated with maternal particulate matter exposure in term neonates.

Conclusion: These findings indicate that pregnant women might be more susceptible to particulate matter during the second trimester which may lead to decreased neonatal birth weight.

Keywords: Birth weight; Gestational age; Particulate matter exposure; Second trimester.