Risk Of Fetal Neural Tube Defects Research Articles

Maternal 25-hydroxyvitamin D level and the occurrence of neural tube defects in Tunisia

ObjectiveTo determine whether low vitamin D levels in pregnant women are associated with the occurrence of neural tube defects (NTDs) in Tunisia. MethodsIn a prospective study, pregnant women were recruited at a center in Tunis between January 1, 2012, and December 30, 2013. Women carrying a fetus with a severe NTD were recruited before elective termination. Matched, healthy pregnancy women were enrolled into a control group. Plasma levels of 25-hydroxyvitamin D were measured by a competitive chemiluminescence immunoassay. ResultsOverall, 68 women formed the NTD group and 64 the control group. The mean maternal vitamin D level was significantly lower in the NTD group (20.65±10.25nmol/L) than in the control group (28.30±13.82nmol/L; P<0.001). Vitamin D deficiency was recorded for 53 (78%) women in the NTD group and 39 (61%) in the control group. Vitamin D insufficiency was recorded for 15 (22%) women in the NTD group and 20 (31%) in the control group. Vitamin D sufficiency was found only in the control group (n=5 [8%]; P<0.001). ConclusionThe findings confirm an association between a decreased vitamin D level in pregnant women and the risk of fetal NTDs.

Maternal genetic polymorphisms of phase II metabolic enzymes and the risk of fetal neural tube defects

Maternal exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with the risk of fetal neural tube defects (NTDs). Whether maternal genetic variants related to PAH metabolism contribute to the development of fetal NTDs remains unclear. We conducted a case-control study in a Chinese population to examine the association of selected maternal genetic variants of phase II enzymes involved in the elimination of the metabolic intermediates of these chemicals with fetal NTD risk, and to evaluate possible interaction of the genetic variant and maternal exposure to indoor air pollution from coal combustion and smoking (IAPCC). Blood samples were collected from 534 NTD case mothers and 534 control mothers and assayed for 12 polymorphisms of 5 genes encoding phase II enzymes. We found that the rs9282861 GG genotype of SULT1A1 was associated with an elevated risk of total NTDs (odds ratio [OR] = 2.12, 95% confidence interval [CI]: 1.49-3.00), compared with the GA genotype. The SULT1A1 rs9282861 variant showed a significant additive interaction with maternal exposure to IAPCC for NTD risk, with a relative excess risk of interaction of 1.20 (95% CI 0.23-2.18), and the OR for the joint effect of high-level IAPCC exposure and the GG genotype was 8.37 (95% CI: 3.63-19.28). Maternal SULT1A1 polymorphism is associated with the risk of fetal NTDs, and has an additive-scale interaction with maternal IAPCC exposure for NTD risk.

Fewer Neural-Tube Defects in Canada After Folic Acid Fortification

Daily consumption of 400 μg of folic acid before conception reduces the risk for fetal neural-tube defects, but many women do not consume the

Vitamin B12 insufficiency and the risk of fetal neural tube defects.

Although maternal folate insufficiency is a risk factor for fetal neural tube defects (NTDs), there is controversy about whether vitamin B12 (B12) insufficiency is also associated with an increased risk of NTDs. To investigate whether low maternal B12 is associated with an increased risk of fetal NTDs. Systematic review. A systematic search of Medline between 1980 and October 2002, with an examination of the citations of all retrieved studies. Studies were included that: (i) used a cohort or case-control design; (ii) included case mothers with a prior or current NTD-affected pregnancy; (iii) assessed a group of unaffected 'controls'; and (iv) measured the vitamin B12 status of all participants. Overall, 17 case-control studies were included, mean sample size 33 cases and 93 controls. In 5/6, mean amniotic fluid B12 concentration was significantly lower in case mothers than in controls. Of 11 that measured maternal serum or plasma B12, three observed a significantly lower mean concentration in case mothers vs. controls, while five others found a non-significant lower trend in the case group. One study observed a significantly higher mean concentration of maternal serum methylmalonic acid among the maternal cases, while another found a non-significant lower mean concentration of plasma holo-transcobalamin. Five studies estimated the risk of NTDs in relation to low B12 or B12-related metabolic markers: it was significantly increased in three studies, with a non-significant trend in the fourth. There seems to be a moderate association between low maternal B12 status and the risk of fetal NTDs. However, several design limitations, and the inclusion of few study participants, may have under-represented this. A large observational study, using reliable and valid indicators of B12 status in early pregnancy, could best assess the association between B12 insufficiency and the risk of fetal NTDs.

Neural‐tube defects and vitamins: the need for a randomized clinical trial

It has been suggested that taking extra vitamins around the time of conception may reduce the risk of fetal neural-tube defects. We have examined the evidence for this and conclude that there is considerable doubt about the efficacy of such a regimen. Also, it cannot be assumed that the taking of extra vitamins has no adverse medical effects. We give reasons for our view that a large randomized clinical trial is ethical and the only satisfactory way of resolving the matter. The Medical Research Council is currently conducting such a study in centres in Britain and abroad, involving women who have already had a pregnancy with a fetal neural-tube defect. The design of the Medical Research Council study is described briefly.