Neural tube defects and elevated homocysteine levels in amniotic fluid

OBJECTIVE: Our purpose was to study maternal blood and amniotic fluid concentrations of homocysteine and relevant vitamins in relation to neural tube defects. STUDY DESIGN: Concentrations of total homocysteine, folate, and vitamins B12 and B6 were measured in maternal blood and amniotic fluid of 27 women carrying a fetus with a neural tube defect and 31 control women carrying a healthy fetus. RESULTS: The mean total homocysteine concentration in amniotic fluid of the study group was significantly higher than that of the control group. The mean concentrations of total homocysteine in blood and the vitamins folate, B12, and B6 in, respectively, blood and amniotic fluid were not significantly different between the grous. The mean concentrations of homocysteine and vitamin B6 were significantly lower in amniotic fluid than in blood groups, whereas vitamin B12 in amniotic fluid was higher than in blood. CONCLUSION: These results support the hypothesis that at least the cause of a subset of neural tube defects could reside in a primary or secondary maternal or fetal derangement of homocysteine metabolism.