Investigation of folate intake and metabolism in women who have had two pregnancies complicated by neural tube defects

Abstract

Object To investigate folate intake and blood levels of folic acid and vitamin C in women with and without a history of two NTD‐affected pregnancies and to measure the increase in serum folate following ingestion of orange juice. Subject Sixteen women with a history of two NTD‐affected infants and 16 controls with no such history, none of whom were either pregnant or taking vitamin supplements. The orange juice loading test was carried out on eight matched pairs. Main outcome measures Dietary intake of folate was assessed by questionnaire and blood levels of folate and vitamin C were measured. Results There was no evidence of decreased intake of folate in subjects who had had two NTD‐affected pregnancies. In controls, both serum and red cell folate showed significant correlation with dietary folate, while in subjects there was no such correlation. Subjects also had smaller increases in serum folate following an oral load than controls, although the differences were not significant. Conclusion Women who have had two NTD‐affected pregnancies may have defective folate metabolism. Further investigations on short term utilisation of ingested food folates in these women are required.

Genetic polymorphisms in methylenetetrahydrofolate reductase and methionine synthase, folate levels in red blood cells, and risk of neural tube defects

“…In a study of women who had had two NTD pregnancies, no difference was seen in serum or RBC folate among women with different pregnancy outcomes, but an altered relation to dietary intake of folate was observed between the groups [Yates et al, 1987]. In another study, the finding of a negative correlation between the RBC folate in mothers and the number of infants affected with NTD could not be adequately accounted for by the dietary intake [Wild et al, 1994]. Daly et al [1995] have suggested that maternal RBC folate in early pregnancy is a marker of NTD risk, in a continuous dose-response relationship.…”

Involvement of deprivation and environmental lead in neural tube defects: a matched case-control study

“…In another investigation women in early pregnancy in north London26were found to have the lowest means for erythrocyte and serum folate in April to June, but correlation with estimated dietary intake was weak. Sometimes folic acid does not prevent recurrences, and recently an investigation of 16 women who had two infants affected with neural tube defects despite taking vitamin supplements for prevention was reported 27. It was suggested that they might have defective folate metabolism.…”

Body mass index and serum folate in childbearing age women

“…There are suggestions, however, that abnormalities in folate distribution or metabolism which make the stored folate in maternal tissues less available to the growing embryo may be the responsible mechanism in some cases of NTD-affected pregnancies [4,6,14]. Studies of women with a history of NTD-affected pregnancies have noted a decreased serum/red blood cell folate ratio [15,16] and a slowed rise of serum folate level in response to folate intake [17]. As the folate in serum is the direct source of this micronutrient to the growing embryo, variations in serum folate levels may have a profound effect on neural tube development in the first few weeks of gestation [17].…”