The C677T MTHFR gene mutation is not predictive of risk for recurrent fetal loss.

We have investigated the potency of the C677T mutation in the methylene tetrahydrofolate reductase (MTHFR) gene as a genetic risk factor in women with a history of early (</=12 weeks gestation) and/or late (>12 weeks gestation) recurrent miscarriage (three or more consecutive pregnancy losses). Fifty-seven of the total 173 (32. 9%) patients were heterozygous for the MTHFR mutation, 14/173 (8.1%) were homozygous (allele frequency 0.25). The prevalence of the MTHFR mutation in these women did not differ significantly from that in the control group of parous women with uneventful pregnancies, where 30/67 (44.8%) were heterozygous and 6/67 (9.0%) homozygous for the mutation (allele frequency 0.31; odds ratio for homozygous T/T 0.90, 95% CI 0.30-2.4). There was no association between the trimester of pregnancy loss and MTHFR genotype. We conclude that the C677T MTHFR mutation is not a risk predictor in women with a history of early or late recurrent miscarriage.