Impact of 677C>T mutation of the 5,10- Methylenetetrahydrofolate Reductase (MTHFR) on IVF outcome: is a screening necessary for all infertile women?

Aim: Polymorphisms of genes connected to folate's metabolism may alter the beneficial effect of folic acid on the methyl groups cycle. The most common variation is the 677C>T polimorphism of the gene of the 5,10-methylentetrahydrofolate reductase (MTHFR). The aim of this study is to investigate of what influence, if any, does MTHFR 677C>T mutation haves on female fertility and on IVF outcome. Results: Data of 273 patients were retrospectively analyzed. The study group (group A) consisted of 103 women, homozygous for MTHFR 677C>T mutant genotype. The control group (group B) consisted of 170 patients without the mutation. A longer stimulation duration was found in group A and the total amount of recombinant follicle stimulating hormone (r-FSH) needed was appreciably higher. The fertilization rate was significantly higher in group B, although implantation rate and clinical pregnancies were similar in both groups. Conclusions: Alteration of inherited thrombophilic factors are connected with early pregnancy loss and IVF implantation failure. Our study showed an abortion rate higher, but not statistically significant, in group A. Based on these findings, our study suggests that MTHFR 677C>T mutation does not affect IVF outcome and patients without thrombophilic risk factors undergoing an IVF cycle shouldn’t all be screened for thrombophilic disorders