Combined exposure to PM and PM in reductions of physiological development among preterm birth: a retrospective study from 2014 to 2017 in China.

Background: Preterm birth (PTB) has been linked with ambient particulate matter (PM) exposure. However, data are limited between physiological development of PTB and PM exposure.

Methods: Trimester and season-specific PM exposure including PM and PM was collected from Jiaxing between January 2014 and December 2017. Information about parents and 3,054 PTB (gestational age < 37 weeks) outcomes such as weight (g), head circumference (cm), chest circumference (cm), height (cm) and Apgar 5 score were obtained from birth records. We used generalized linear models to assess the relationship between PTB physiological developmental indices and PM, PM and their combined exposures. A binary logistic regression model was performed to assess the association between exposures and low birth weight (LBW, < 2,500 g).

Results: Results showed that there were 75.5% of low birth weight (LBW) infants in PTB. Decreased PM and PM levels were found in Jiaxing from 2014 to 2017, with a higher PM level than PM each year. During the entire pregnancy, the highest median concentration of PM and PM was in winter (61.65 ± 0.24 vs. 91.65 ± 0.29 μg/m) followed by autumn, spring and summer, with statistical differences in trimester-specific stages. After adjusting for several potential factors, we found a 10 μg/m increase in joint exposure of PM and PM during the entire pregnancy associated with reduced 0.02 week (95%CI: -0.05, -0.01) in gestational age, 7.9 g (95%CI: -13.71, -2.28) in birth weight, 0.8 cm in height (95%CI: -0.16, -0.02), 0.05 cm (95%CI: -0.08, - 0.01) in head circumference, and 0.3 (95%CI: -0.04, -0.02) in Apgar 5 score, except for the chest circumference. Trimester-specific exposure of PM and PM sometimes showed an opposite effect on Additionally, PM (OR = 1.37, 95%CI: 1.11, 1.68) was correlated with LBW.

Conclusion: Findings in this study suggest a combined impact of fine particulate matter exposure on neonatal development, which adds to the current understanding of PTB risk and health.