In a pilot study, we demonstrated that metabolomic analysis of second trimester maternal serum from patients who developed preeclampsia had significant elevations in multiple unsaturated fatty acids and medium chain acylcarnitines and reduction in certain bile acids when compared to controls. A drawback to that pilot study was that patients were not fasting, thus these metabolomic differences might be confounded by the last meal consumed. The objective of this study is to validate the metabolomic findings from the pilot study among fasting gravida. We prospectively collected fasting serum samples from 37 pregnant patients at 24-28 weeks gestation. 9 developed pre-eclampsia later in pregnancy and 28 served as controls. These samples were analyzed using Q-TOF mass spectrometry in a targeted protocol. We used Student’s t-test to compare the metabolites between the two groups. We obtained fasting serum from 9 patients who later developed preeclampsia and 28 controls. Maternal age, parity, and BMI were similar between the two groups. Figure 1 is a heat map representing a summary of the results of this fasting study. We found no statistically significant differences in the targeted unsaturated fatty acids and medium chain acylcarnitines. Among bile acids, cholic acid levels were four times lower in the preeclampsia cohort compared to controls (p=0.03). Cholic acid was significantly lower in pregnancies that later developed preeclampsia compared to controls. Other metabolites discovered in the non-fasted discovery cohort were not validated in the fasted validation cohort. Taken together, the data from the two cohorts may suggest that pregnant women who later develop preeclampsia may metabolize fatty acids less effectively, thus leading to elevations in the circulating fatty acids breakdown molecules, and this difference in metabolism is less dramatic in the fasting state. Performing metabolomic profiling in fasting and fed pregnant women can further elucidate this postulation and correlate metabolomic profiles with pregnancy outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)