Folate and vitamin B-12 status of women in Newfoundland at their first prenatal visit

Background: Newfoundland has one of the highest rates of neural tube defect s in North America. Given the association between low maternal folic acid l evels and neural tube defects, a cross-sectional study was conducted to obt ain baseline data on the folate and vitamin B-12 status of a sample of wome n in Newfoundland who were pregnant. Methods: Blood samples were collected between August 1996 and July 1997 fro m 1424 pregnant women in Newfoundland during the first prenatal visit (at a pproximately 16 weeks' gestation); this represented approximately 25% of th e women in Newfoundland who were pregnant during this period. The samples w ere analysed for serum folate, vitamin B-12, red blood cell folate and homo cysteine. Results: Median values for serum folate, red blood cell folate and serum vi tamin B-12 were 25 nmol/L, 650 nmol/L and 180 pmol/L, respectively. On the basis of the interpretive criteria used for red blood cell folate status, 1 57 (11.0%) of the 1424 women were deficient (< 340 nmol/L) and a further 18 0 (12.6%) were classified as indeterminate (340-420 nmol/L). Serum homocyst eine levels, measured in subsets of the red blood cell folate status groups , supported the inadequate folate status. Serum vitamin B-12 levels of 621 (43.6%) women were classified as deficient or marginal; however, the validi ty of the interpretive criteria for pregnant women is questionable. Interpretation: A large proportion of pregnant women surveyed in Newfoundla nd in 1997 had low red blood cell folate levels.