The toxicity of organophosphate esters (OPEs) on embryonic development is well noted in animal experiments, but epidemiological studies are still lacking. This study evaluated the prenatal exposure of OPEs and its trimester-specific and gender-specific effects on fetal growth. The correlations between OPE exposure and fetal growth were investigated by linear mixed-effect models and multivariable linear regression analyses. Prenatal exposure to tributyl phosphate (TBP) was negatively associated with a z-score of fetal abdominal circumference (AC), biparietal diameter (BPD), femur length (FL), and head circumference (HC). In the second trimester, the serum concentration of TBP was inversely related to the z-score of AC, BPD, and HC. In the third trimester, serum concentration of TBP was inversely related to AC, BPD, and FL z-scores. Prenatal exposure to tri-m-cresyl phosphate (TMCP) was inversely related to the z-score of AC, BPD, and HC. In the second trimester, TMCP was negatively correlated with AC, BPD, FL, and HC z-scores. After stratification by gender, male fetuses were more sensitive to OPE exposure. The above results remained robust after excluding pregnant women who gave preterm birth or those with low or high pre-pregnancy BMI. Our findings suggested that health effects of typical OPEs, particularly TBP and TMCP, should be taken into consideration in future works.
Keywords: critical windows; fetal growth; gender-specific effects; organophosphate esters; repeated measurement.