Prenatal NO2exposure and ultrasound measures of foetal growth: a prospective cohort study in Wuhan, China
研究了中国武汉1001名孕妇，发现孕期二氧化氮暴露与胎儿超声测量的头径、头围、腹围、股骨长和估计体重呈负相关，且女婴和吸烟母亲的影响更强。
<h3>Objectives</h3> To examine the relationship between prenatal nitrogen dioxide (NO<sub>2</sub>) exposure and foetal growth in a prospective cohort of 1001 Chinese women. <h3>Methods</h3> The maternal NO<sub>2</sub> exposure levels were estimated using land-use regression models based on home address. The biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated foetal weight (EFW) were evaluated via ultrasonography. The multiple linear regression model was used to adjust for confounders, and the mixed-effect model was used to assess longitudinal effect. <h3>Results</h3> With a 10 μg/m<sup>3</sup> increase in NO<sub>2</sub> exposure, the BPD, HC, AC, FL and EFW in the second trimester decreased by 0.40 mm (95% CI −0.56 to −0.24), 1.07 mm (95% CI −1.60 to −0.54), 1.02 mm (95% CI −1.57 to −0.48), 0.24 mm (95% CI −0.37 to −0.12) and 7.84 g (95% CI −11.59 to −4.08), respectively; the BPD and HC in the third trimester decreased by 0.26 mm (95% CI −0.50 to −0.02) and 0.71 mm (95% CI −1.37 to −0.06), respectively. The longitudinal analyses showed inverse associations of NO<sub>2</sub> exposure with BPD, HC, AC and FL (all p<0.05). The stratified analyses showed that the effects of NO<sub>2</sub> on the HC, FL and EFW in the second trimester were stronger among female babies and that the effect of NO<sub>2</sub> on EFW in the third trimester was stronger among smoking mothers (all p<0.05). <h3>Conclusions</h3> In this prospective study of Chinese women, maternal NO<sub>2</sub> exposure was inversely associated with foetal growth, and the association was stronger among female babies and smoking mothers.