Abstract: Preeclampsia is a group of diseases consist of hypertension and albuminuria during pregnancy, which is the main cause of the increased maternal and perinatal mortality. Homocysteine (Hcy) is a sulfur-containing amino acid, which is the intermediate metabolite of methionine. Plasma homocysteine levels are affected by methylenetetrahydrofolate reductase gene polymorphism, folic acid and vitamin B12 in pregnant women. The plasma hcy concentration in normal pregnant women was lower than that in non pregnant women. The increase of plasma homocysteine level can damage vascular endothelial cells through oxidative stress, plasma nitric oxide and endothelin imbalance and cystathithione b-synthase/cystathion-glyase/ hydrogen sulfide pathway. Dynamic monitoring of plasma homocysteine levels during pregnancy may provide a new method for early prediction and intervention of preeclampsia.

Key words: Pregnancy, Pre-eclampsia, Hyperhomocysteinemia, Folic acid, Vitamin B12