Folate, Vitamin B12, and Homocysteine Levels in South Asian Women with Growth-retarded Fetuses

Objective: To investigate whether intrauterine growth retardation (IUGR) and preterm delivery in a poor population of South Asia was associated with altered maternal and fetal levels of folate, vitamin B12, and homocysteine.

Subjects And Methods: Hundred and twenty-eight pregnant women from a low socio-economic strata in the city of Lahore, Pakistan were followed with ultrasound of fetal growth from the 12th week of pregnancy. Blood samples were drawn from the woman and the cord at delivery. Serum was analyzed by a chemiluminescent immunoassay for folate and vitamin B12 and by fluorescence polarization immunoassay for total homocysteine (tHcy).

Results: Fourty-six infants showed IUGR. In term, but not preterm, deliveries with IUGR, maternal and cord blood folate levels were half of those in deliveries of normal birth weight infants (P=0.004 and P=0.005). The risk of IUGR was reduced among women with folate levels in the highest quartile (OR 0.31, 95% CI 0.10--0.84). There was no association between vitamin B12 and IUGR. Total homocysteine levels were higher in women delivering IUGR infants (P=0.02). There was an inverse correlation between cord blood folate and tHcy levels (r=-0.26, P=0.006). We also found increased risks for hypertensive illness (OR 3.5, 95% CI 1.4--8.6) and premature delivery (OR 2.5, 95% CI 1.1--6.2) in women in the highest quartile of tHcy.

Conclusions: The occurrence of IUGR increased with low maternal and cord concentrations of folate and high maternal levels of tHcy. Further studies on the effects of vitamin B supplementation through pregnancy are warranted.