Association between MTHFR polymorphisms (MTHFR C677T, MTHFR A1298C) and recurrent implantation failure: a systematic review and meta-analysis

Objective: To investigate whether polymorphism of MTHFR C677T or MTHFR A1298C is associated with recurrent implantation failure (RIF).

Study design: This is a systematic review and meta-analysis. Pubmed, EMBASE, and CNKI (China national Knowledge Infrastructure) were searched for case-control studies that evaluated the associations between MTHFR polymorphisms (MTHFR C677T and MTHFR A1298C) and RIF. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were reported to evaluate the strength of association. Data were synthesized using the random-effect model.

Results: Nine case-control studies consisted of 1812 women were included in the quantitative meta-analyses (754 were RIF patients, 1058 were control participants). The synthesized results showed that polymorphism of MTHFR C677T (allele model: OR 1.23, 95% CI 0.99-1.53; dominant model: OR 1.24, 95% CI 0.99-1.54; recessive model: OR 1.31, 95% CI 0.78-2.12; homozygotic model: OR 1.39, 95% CI 0.84-2.28; heterozygotic model: OR 1.14, 95% CI 0.90-1.45) or MTHFR A1298C (allele model: OR 1.11, 95% CI 0.78-1.59; dominant model: OR 0.91, 95% CI 0.65-1.26; recessive model: OR 2.04, 95% CI 0.90-4.64; homozygotic model: OR 1.86, 95% CI 0.79-4.38; heterozygotic model: OR 0.77, 95% CI 0.59-0.99) was not significantly associated with RIF.

Conclusions: Significant association of MTHFR polymorphisms (including MTHFR C677T and MTHFR A1298C) and RIF could not be confirmed.