Umbilical cord plasma Lysophospholipids and Triacylglycerols Associated with Birthweight Percentiles

Dysregulated transplacental lipid transfer and fetal-placental lipid metabolism affect birthweight, as does maternal hyperglycemia. As the mechanisms are unclear, we aimed to identify the lipids in umbilical cord plasma that were most associated with birthweight. Seventy-five Chinese women with singleton pregnancies recruited into the GUSTO mother-offspring cohort were selected from across the glycemic range based on a mid-gestation 75g oral glucose tolerance test, excluding pre-existing diabetes. Cord plasma were analysed using targeted liquid-chromatography tandem mass-spectrometry to determine relative concentrations of 404 lipid species across 17 lipid classes. Birthweights were standardized for sex and gestational age by local references, and regression analyses adjusted for maternal age, BMI, parity, mode of delivery, insulin treatment, and fasting/2h glucose, with false discovery-corrected p<0.05 considered significant. Ten lysophosphatidylcholines (LPC) and two lysophosphatidylethanolamines were positively associated with birthweight percentiles, while twenty-four triacylglycerols negatively associated with birthweight percentiles. The topmost associated lipid was LPC 20:2 [21.28 (95%CI 12.70, 29.87) percentile increase in standardized birthweight with each SD-unit increase in log10-transformed relative concentration]. Within these same regression models, maternal glycemia did not significantly associate with birthweight percentile. Specific fetal circulating lysophospholipids and triacylglycerols associate with birthweight independently of maternal glycemia, but a causal relationship remains to be established.