The Effects Of Exposure To Trihalomethanes In Drinking Water During The First Trimester On Fetal Growth

ObjectiveA large number of toxicological studies have suggested that exposure to trihalomethanes(THMs) can cause adverse pregnancy outcomes in animals, but the results from epidemiologic study are inconsistent. Early pregnancy is critical for the organ differentiation and development of fetus, and represents a critical window of exposure for implications in adverse health outcomes later in life. Therefore, we conducted the present study to explore the effects of exposure to trihalomethanes in drinking water during the first trimester on fetal growth by using THMs in blood as internal exposure markers and measurements of neonatal growth indicators at birth. MethodsEarly pregnant women who presented to the Xiao-Nan Maternal and Child Care Center for prenatal examination between March and July 2015 were asked to provide a blood sample and complete a questionnaire. Neonatal growth indicators were measured after birth. We used the method of headspace solid-phase micro-extraction gas chromatography(SPME-GC) to measure the levels of 4 THMs [chloroform(TCM), bromodichloromethane(BDCM), dibromochloromethane(DBCM) and bromoform(TBM)] in blood. Multivariable linear model were used to examine the associations between blood THMs and fetal growth characteristics [infant weight, length, birth body mass index(BMI), head circumference and chest circumference]. ResultsTwo hundred pregnant women agreed to participate in the study, and finally 159 women gave birth to a single live birth. The detectable rates of four THMs(TCM, BDCM, DBCM and TBM) in blood of pregnant women are 85.8%, 63.9%, 35.5% and 41.9%, respectively. We found significantly negative dose-response relationships of blood DBCM and TBM with birth weight(p for trend=0.004); DBCM, TBM and BrTHMs with BMI(p for trend=0.004, 0.02, 0.05); and TBM with chest circumstance(p for trend=0.05). Additionally, we found a suggestively negative dose-response relationship between TTHMs and BMI(p for trend=0.06). ConclusionThe present study suggests that maternal exposure to THMs during the first trimester may cause reduction in birth weight, BMI and chest circumstance.