Background Polybrominated diphenyl ethers (PBDEs) are a new class of endocrine disruptors and have been detected in various types of human biological samples across China. Recently, prenatal exposure to PBDEs has been associated with child growth deviation. However, the quantity of such studies is limited and conclusions are inconsistent.

Objective The study is conducted to detect exposure levels of PBDEs in pregnant women in PBDE production areas and examine the potential association between PBDEs exposure in pregnancy and child growth at 8 years of age.

Methods The study included 121 mother-child pairs in Laizhou Wan Birth Cohort (LWBC), a cohort enrolled form September 2010 through December 2013 in Shandong, China. Serum samples were collected in the third trimester. Concentrations of PBDEs (BDE-28, BDE-47, BDE-85, BDE-99, BDE-100, BDE-153, BDE -154, BDE-183) in the samples were measured by gas chromatography-electron capture negative ion-mass spectrometry, and the concentration of Σ₅PBDEs was calculated (sum of five PBDEs of detection rates >85%:BDE-28, BDE-47, BDE-99, BDE-100, and BDE-153). Child height, weight, waist circumference, and body fat percentage were measured and body mass index (BMI) was calculated at follow-up visits during July to September 2019. The association between PBDEs exposure levels in late pregnancy and child growth at 8 years of age were quantified by multiple linear regression models.

Results The PBDEs congeners were detected in all maternal serum samples to varying degrees. The detection frequencies of BDE-153 and BDE-99 were both 95.87%, which were the highest among the congeners, and the medians (P₂₅, P₇₅) were 4.86 (2.97, 9.43) and 3.54 (2.16, 5.35) ng·g^-1, respectively. The mean child age was (8.14±0.47) years. Maternal serum BDE-85 and BDE-99 concentrations were positively associated with child weight, and the regression coefficient b and 95% confidence interval (CI) were 8.63 (0.95-16.30) and 8.50 (0.06-16.94) respectively. Maternal serum BDE-47, BDE-85, BDE-99, BDE-153, Σ₅PBDEs concentrations were positively associated with child height, and the b and 95%CI were 7.79 (1.74-13.85), 6.12 (0.01-12.24), 9.69 (3.17-16.21), 6.75 (0.21-13.29), and 12.30 (4.26-20.34), respectively. Maternal serum BDE-85 concentration was positively associated with child waist circumference, and the b and 95%CI was 12.94 (3.70-22.19). After sex stratification, maternal serum BDE-47, BDE-99, BDE-100, and Σ₅PBDEs concentrations were positively associated with boys' height, and maternal serum BDE-85 concentration was positively associated with boys' waist circumference (P<0.05). While no associations were found in girls. There were sex-specific associations between maternal serum BDE-47, BDE-99, BDE-153, and Σ₅PBDEs concentrations and child height, and between maternal serum BDE-85 concentration and child waist circumference (P_int<0.05).

Conclusion Pregnant women in LWBC are generally exposed to PBDEs. PBDEs exposure in late pregnancy may significantly and sexspecifically increase the weight, height, waist circumference in 8-year-old children.