THURSDAY, July 22 (HealthDay News) -- Women who have functional single-nucleotide polymorphisms in folate-related genes as well as lifestyle factors that may alter folate metabolism appear to be at increased risk of having a fetus with a congenital heart defect (CHD), according to a study published in the August issue of Obstetrics & Gynecology.

In a population-based case-control study, Charlotte A. Hobbs, M.D., of the Arkansas Children's Hospital Research Institute in Little Rock, and colleagues evaluated 572 women with CHD-affected pregnancies (case group) and 363 women who had live births that were unaffected by any birth defect (control group). The researchers genotyped DNA samples for single-nucleotide polymorphisms in genes encoding for folate pathway enzymes.

Compared with women in the control group, the researchers found that women in the case group were 1.5 times more likely to be obese (body mass index ≥30 kg/m²). In addition, compared to normal-weight women carrying a CC genotype, obese women carrying the MTHFR TT genotype were 4.6 times more likely to have a CHD-affected pregnancy. Obese women carrying one or two copies of the A allele in the BHMT polymorphism were 1.8 times more likely than normal-weight women with a BHMT GG genotype to have a CHD-affected pregnancy. In addition, women who smoked or drank alcohol and carried a TCII CG or GG genotype were more likely to have a CHD-affected pregnancy compared to women who smoked or drank and carried a CC genotype.

"Results indicate that functional polymorphisms in folate-related genes increase the risk of having a fetus with CHD when maternal lifestyle factors that alter folate metabolism are present," the authors write.

Abstract
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