HILIC-MS-based shotgun metabolomic profiling of maternal urine at 9-23 weeks of gestation - establishing the baseline changes in the maternal metabolome

In this data-rich age it is no longer necessary to methodically isolate, characterize and measure specific molecules. What is important is to identify which of the hundreds or thousands of resolved and measured unknown' molecules are potentially associated with the pathophysiology of interest. We have taken LC-MS data from pregnancy urine and applied SIMCA P+ data analysis software in shotgun metabolomics to search the large amount of data for significant metabolite changes that occur in the transition from the first to early second trimester of pregnancy. Seventy-two individual urine samples were examined spanning 9-23 weeks of gestation. Three-hundred and eighty-three ions were identified and variations were mapped between profiles of different gestational age and the significance quantified. In urine collected during pregnancy, the transition from first to early second trimester revealed a relatively steady pattern of metabolites except for four that showed a dramatic fall in abundance as pregnancy progressed from the first to second trimester. The pattern of changes in urinary metabolites identified by Zwitterionic Hydrophilic Liquid Interaction Chromatography (ZIC-HILIC) coupled to mass spectrometry was evaluated and we established a baseline of changes from which a search for metabolomic markers associated with clinical pathologies of pregnancy can be made as a part of wider ultraomics study. Copyright (c) 2014 John Wiley & Sons, Ltd.