Relationship between chlorpyrifos exposure level in pregnancy and neonatal anthropometric indices at birth

Background The organophosphorus pesticide chlorpyrifos (CPF) is widely used in agricultural production, and the resulting environmental pollution and health risk are serious concerns.

Objective This study aims to investigate the relationship between CPF exposure level in pregnancy and anthropometric indices of newborns at birth.

Methods A total of 1 100 mother-child pairs in Jiangsu Sheyang Mini Birth Cohort Study were enrolled as study subjects. Length, head circumference, and birth weight of the newborns were measured by professional midwives, and body mass index (BMI) and ponderal index (PI) were calculated. A questionnaire survey was conducted to collected maternal socio-demographic characteristics and pregnancy variables. Spot urine samples were collected during pregnancy. Maternal urinary concentrations of 3, 5, 6-trichloro-2-pyridinol (TCPy, a specific metabolite of CPF) were measured by gas chromatography tandem mass spectrometry. Generalized linear models were used to evaluate the relationships of prenatal exposure to TCPy with anthropometric indices and the risk of macrosomia.

Results TCPy was detected in all maternal urine samples. The creatinine-adjusted TCPy levels ranged from 0.14 to 135.44 μg·g^-1, the median (P₂₅, P₇₅) was 6.96 (4.35, 11.75) μg·g^-1, and the geometric mean was 7.02 μg·g^-1. The birth weight, body length, head circumference, BMI, and PI of the newborns were (3 490.49±442.57) g, (51.23±2.35) cm, (34.64±1.45) cm, (13.29±1.41) kg·m^-2, and (2.60±0.32) g·cm^-3, respectively. There were 137 macrosomia cases (12.5%). The results of generalized linear model indicated that the prenatal TCPy level was positively associated with the PI b (95% CI): 0.062 (0.012-0.112), P=0.016 and BMI b (95% CI): 0.270 (0.053-0.486), P=0.015. The P values for sex-interaction were all lower than the level of significance (α=0.10) for body length (P=0.088), BMI (P=0.033), PI (P=0.013) models. In the sex-stratified analysis, the TCPy level was positively associated with PI and BMI in boys b (95% CI): 0.111 (0.043-0.179), P=0.001; b (95% CI): 0.443 (0.138-0.748), P=0.001, but no associations were found in girls (P > 0.05).

Conclusion Prenatal CPF exposure may affect intrauterine development, and this health effect may have sex differences.