Determination of organochlorine pesticides in human umbilical cord and association with orofacial clefts in offspring.

Studies based on questionnaires suggested that maternal exposure to pesticides increases the risk for orofacial clefts (OFCs). However, whether organochlorine pesticides (OCPs) exposure in vivo affects the occurrence of OFCs remains unclear. The aims of this study are to investigate the association of OCP exposure with the risk of OFCs by examining the concentrations of OCPs in human umbilical cords, and investigate the potential dietary sources of OCPs in umbilical cord tissues. A case-control study consisting of 89 OFC cases and 129 nonmalformed controls with available tissues of umbilical cord was conducted. Concentrations of twenty specific OCPs were determined in the umbilical cord by gas chromatograph-mass spectrometry, and seven OCPs with detection rate larger than 50% were included in analyses. The individual effect and joint effect of multiple OCPs in umbilical cords on the risk for OFCs were investigated using multivariate logistic models and Bayesian Kernel Machine Regression (BKMR). No difference was found in the median levels of ΣOCPs between cases (1.04 ng/g) and controls (1.03 ng/g). No significant associations were observed between levels of OCPs in umbilical cords and risk for OFCs in either multivariate logistic models or BKMR models. Maternal consumptions of beans or bean products were positively correlated with levels of β-hexachlorocyclohexane, heptachlor epoxide, p,p'-DDE, and ∑OCPs in umbilical cord, respectively. In conclusion, we didn't find the association between in utero exposure to OCPs and the risk for OFCs. Maternal consumptions of beans or bean products may be a source of OCPs exposure.