Folic acid, Vitamin B(12), and homocysteine in smoking and non-smoking pregnant women.

Introduction: Lower plasma levels of vitamins may result in hyperhomocysteinemia, a known risk factor in pregnancy. As smoking may alter nutrition, we were interested in its effect on folate and Vitamin B(12) in pregnancy.

Materials And Methods: A cross-sectional study of 62 smoking and 76 non-smoking healthy pregnant women. Serum folic acid, Vitamin B(12) and homocysteine were measured at four points in pregnancy: 0-10, 11-20, 21-30 and 31-40 weeks.

Results: Folate concentrations of the smoking women decreased continuously during pregnancy, and were significantly lower than those of non-smoking women during the last 30 weeks. Vitamin B(12) levels decreased significantly in both groups. The homocysteine levels were higher in the smoking group during the second-half of pregnancy.

Discussion: Smoking women have lower and decreasing folate levels during pregnancy, possibly as a result of lower intake of these nutrients. Lower folate levels can lead to hyperhomocysteinemia, a known risk factor for several complications in pregnancy. This is an other important reason to convince pregnant women to refrain from smoking.