Quantification of ethyl glucuronide, ethyl sulfate, nicotine, and its metabolites in human fetal liver and placenta

Purpose Tobacco and alcohol use during pregnancy is serious public health concerns and result in adverse developmental outcomes. Identifying in utero exposure is often achieved through meconium analysis or via maternal self-report. In this study, we analyzed fetal liver and placenta to examine second trimester alcohol and smoking exposure. Methods A validated liquid chromatography-tandem mass spectrometry method for simultaneous analysis of nicotine and its metabolites and alcohol markers (ethyl glucuronide: EtG and ethyl sulfate: EtS) was employed to analyze 193 fetal liver and 48 placenta (n = 47 paired) samples from electively terminated pregnancies. Results EtG, EtS, and nicotine markers' limits of detection were 0.7-20 ng/g in fetal samples. Ninety-eight fetal liver and 23 placenta samples were EtG/EtS-positive, while 137 liver and 25 placenta samples were positive for tobacco exposure. When both alcohol markers were present in samples, EtG/EtS ratios were 1.6-11.1 in 17 livers and 2.5-31.1 in 10 placentas. Median (range) summed tobacco marker concentrations were 422 (1.0-2776) and 154 (1.61621) ng/g in livers and placentas, respectively. Median EtG and nicotine marker concentrations were higher in liver than placenta in paired samples. Strong evidence of exposure occurred in 11 and 22 pairs, respectively, when both samples were positive for alcohol and/or tobacco markers. Conclusions These paired fetal liver and placenta alcohol and tobacco data provided a unique means for examining the effects of in utero exposure, a critical first step in selecting fetal samples for proteomic and RNA sequencing studies that could provide mechanisms for adverse developmental outcomes.