Homocysteine During the Third Trimester is a Risk Factor for Preeclampsia: A Prospective Study

Background: The purpose of this study was to investigate the risk factors for elevating homocysteine during pregnancy and the relative effects on preeclampsia.Method: This is a prospective study that only covers pregnant women withsingletonwho received regular prenatal care from July to September 2018 exclusively at IPMCH(N=1142). Homocysteine, folic acid and vitamin B12 were tested in the 1st trimester (10-14 weeks), 2nd trimester (24-28 weeks), and 3rd trimester(30-34 weeks), respectively, and MTHFR genes (rs1801133, rs1801131, rs17367504) were detected. Therefore, the analysis of this case includesthe variation in Hcylevels during pregnancy, risk factors for elevating homocysteine and the risk factors on preeclampsia.Results: (1) Homocysteinewas lowest in the 1st trimester. (2) Homocysteine was negatively correlated with folic acid (r=-0.17, p<0.001) and vitamin B12 (r=-0.15, p<0.001) in the same trimester. (3) Heterozygous CT (p=0.025, 95% CI 0.018,0.275) and homozygous TT (p<0.001, 95% CI 0.185,0.501) in MTHFR rs1801133 both caused an increase inHcy. G-spot mutations in MTHFR rs17367504 caused a decline inhomocysteine. (4) Homocysteine in the 3rd trimester significantly increased the risk of preeclampsia (OR = 1.2, 95% CI 1.01,1.42), particularly early-onset preeclampsia (OR = 3.63, 95% CI 1.71,7.71) and severe preeclampsia (OR = 3.63, 95% CI 1.71,7.71).Conclusions: The variation inhomocysteine level has a direct impact on preeclampsia,especially early-onset preeclampsia and severe preeclampsia, in the3rd trimester, and MTHFR, folic acid and vitamin B12 were the three most critical factors responsible for the changing homocysteine levelsduring pregnancy.