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.
Subjects: 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.