Maternal homocysteine before conception and throughout pregnancy predicts fetal homocysteine and birth weight

Background: Increased homocysteine has been associated with pregnancy complications. Methods: We investigated prospectively the effect of maternal homocysteine on normal pregnancy outcome. The study included 93 women and their offspring; 39 of the women took folic acid during the second and/or third trimesters of pregnancy. We measured homocysteine at preconception; at weeks 8, 20, and 32 of pregnancy; during labor; and in the fetal cord; we also recorded birth weight. Results: Geometric mean (SE) maternal total homocysteine (tHcy) increased between 32 weeks of pregnancy and labor [7.98 (1.05) mumol/L in unsupplemented women and 6.26 (1.07) mumol/L in supplemented women; P < 0.0001 for both]. Fetal tHcy was lower than maternal tHcy [6.39 (1.06) mumol/L in unsupplemented pregnancies (P < 0.0001), and 5.18 (1.06) mumol/L in supplemented pregnancies (P < 0.05)]. Maternal tHcy was correlated from preconception throughout pregnancy (8 weeks, r = 0.708; 20 weeks, r = 0.637; 32 weeks, r = 0.537; labor, r = 0.502; P < 0.0001 for all time points) and with fetal tHcy [preconception, r = 0.255 (P < 0.05); 8 weeks, r = 0.321 (P < 0.01); 20 weeks, r = 0.469; 32 weeks, r = 0.550; labor, r = 0.624 (P < 0.0001)]. Mothers in the highest tHcy tertile at 8 weeks of pregnancy were three times [odds ratio, 3.26 (95% confidence interval, 1.05-10.13); P < 0.05] and at labor were four times [3.65 (1.15-11.56); P < 0.05] more likely to give birth to a neonate in the lowest birth weight tertile. Neonates of mothers in the highest tHcy tertile at labor weighed, on average, 227.98 g less than those of mothers in the low and medium tertiles (P = 0.014). Conclusions: Supplemented mothers had lower tHcy at labor than unsupplemented mothers, as did their neonates. Maternal and fetal tHcy was significantly correlated throughout the study. Neonates of mothers in the highest tertile of homocysteine weighed less. (C) 2004 American Association for Clinical Chemistry