Folate and vitamin B₁₂ concentrations in maternal and fetal blood, and amniotic fluid in second trimester pregnancies complicated by neural tube defects

Abstract

Objective To investigate maternal and fetal folate and vitamin B12 concentrations in pregnancies affected by neural tube defects (NTD). Design Measurement of folate and vitamin B12 concentrations in amniotic fluid, fetal blood and maternal blood samples in midgestation. Subjects 32 women undergoing termination of pregnancy at 14–21 weeks gestation for social reasons (n = 24) or for fetuses with neural tube defects(n = 8). Interventions Fetoscopy before intra‐amniotic injection of prostaglandins. Results In normal pregnancies there was a positive correlation between maternal and fetal serum folate, and the fetal serum and red blood cell folate concentrations were higher than the maternal. There were no differences in amniotic fluid, maternal blood or fetal blood folate concentrations between pregnancies with NTD and normal pregnancies. Although amniotic fluid vitamin B12 was lower in pregnancies with NTD, maternal serum vitamin B12 concentration was not reduced. Conclusion In this small group of pregnancies with NTD at mid‐gestation there is no evidence to suggest folate or vitamin B12 deficiency.

Maternal-Fetal Folate Status and Neural Tube Defects: A Case Control Study

“…This is in accordance with some previous studies [19,20], but other investigators have failed to demonstrate a RBC folate deficiency in moth ers of NTD fetuses [12,18]. In the latter stud ies, negative results may have been due to the small number of cases [18], the use of immu nologic rather than biologic folate assays, or the fact that some NTD mothers were sam pled in the postpartum period and had re ceived folate supplements after delivery [12], Because maternal folate levels tend to de crease throughout gestation [21], matching cases with controls of similar gestational age is also likely to have improved the sensitivity of our study. A minor decrease in maternal se rum folate was also observed in our study in the NTD group, but this did not reach statisti cal significance, probably due to the small number of cases.…”

“…Surprisingly, subsequent studies on mater nal folate levels led to confusing results. Se rum folate levels in mothers of infants with NTDs were found to be either in the normal range [11,12,[15][16][17][18] or lower than normal controls [19,20], Similarly, maternal red cell folate levels were reported to be either normal [12,18] or lower than controls [5,20].…”

“…Studies on fetal serum and erythrocyte fo late concentrations have not detected a signif icant difference between fetuses affected by NTDs and controls [17,18].…”

Neural tube defects and folate: case far from closed

“…Several clinical studies indicate that folate concentrations in postpartum serum and red blood cells are lower among women who have previously had a child with an NTD [28][29][30] ; however, there have been conflicting results, with some studies failing to find such an association [31][32][33][34][35] . Whether it is a low maternal intake or altered absorption/metabolism of folate that is responsible for the observed association with NTD risk has yet to be established 36 .…”

FASD: folic acid and formic acid — an unholy alliance in the alcohol abusing mother

“…Fetal folate levels (cord blood levels) are 2-to 4-fold higher relative to maternal blood levels (Economides et al 1992;Guerra-Shinohara et al 2002;Stark et al 2007). Folate deficiency during pregnancy is associated with abnormalities in the fetus (Greenberg et al 2011;Safi et al 2012).…”