Relationships of prenatal organophosphate ester exposure with pregnancy and birth outcomes: A systematic scoping review of epidemiological studies.

Exposure to organophosphate esters (OPEs) during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes. However, relevant investigations are scarce, and the findings are inconsistent. We aimed to conduct a scoping review to provide an overview of these associations. Electronic databases, including MEDLINE (through PubMed), Web of Science, and CNKI (China National Knowledge Infrastructure), were searched from inception to March 2022 and updated in July 2022. A total of 8 studies (1860 participants) were included. Limited evidence indicates that OPE exposure during pregnancy may be negatively associated with both maternal and neonatal triiodothyronine and tetraiodothyronine concentrations but positively associated with thyroid-stimulating hormone concentrations. OPE exposure during pregnancy may be associated with lower insulin concentrations. OPE exposure during pregnancy was associated with gestational age in a sex-specific manner. Intrauterine OPE exposure might increase the risk of preterm birth in female infants but decrease the risk of preterm birth in male infants. Prenatal OPE exposure might be associated with an increased risk of low birth weight. The current scoping review suggests that OPE exposure during pregnancy may disturb pregnancy and birth health, including adverse thyroid function and birth size. Because of the limited evidence obtained for most associations, additional studies followed by a traditional systematic review are needed to confirm these findings.