Maternal serum folate and vitamin B12 concentrations in pregnancies associated with neural tube defects.

Serum folate and vitamin B12 concentrations in early pregnancy were compared for 32 mothers with pregnancies affected by neural tube defects and 395 randomly selected pregnant control women from the same maternity hospitals. No significant differences were found between the affected mothers and the controls in the median values and frequency distributions of either vitamin. Sixteen of the samples from mothers whose infants had neural tube defects were taken between 9 and 13 weeks' gestation and 11 of these had both serum folate and vitamin B12 concentrations within the normal ranges for our laboratory. These findings are discussed in relation to the concept of folate deficiency as a major factor in the aetiology of neural tube defects.