Changes in homocysteine levels during normal pregnancy, ,

Objective: The objective of this study was to determine the changes in total plasma homocysteine concentration that occur during normal pregnancy. Study Design: In this cross-sectional study homocysteine was measured in 155 normal women in the first, second, and third trimesters and in nonpregnant controls. In addition, albumin, serum B12 , serum folate, and red blood cell folate concentrations were measured and correlated to homocysteine values. Results: The mean homocysteine concentration (in micromoles per liter) was 5.6 (95% confidence interval 3.9-7.3) at 8-16 weeks’ gestation, 4.3 (95% confidence interval 3.5-5.3) at 20-28 weeks’ gestation, 5.5 (95% confidence interval 3.3-7.5) at 36-42 weeks’ gestation, and 7.9 (95% confidence interval 6.2-9.6) in the nonpregnant control group. Homocysteine was significantly lower in all 3 trimesters of pregnancy compared with nonpregnant controls (P< .001). Homocysteine levels were directly correlated with albumin levels, which decreased during pregnancy. Homocysteine concentrations were decreased in subjects taking folic acid supplementation. Conclusion: Serum concentrations of homocysteine decrease during pregnancy. This occurs in association with the physiologic fall in albumin during pregnancy, as well as with folic acid supplementation. (Am J Obstet Gynecol 1999;180:660-4.)