Meta-analysis of the methylenetetrahydrofolate reductase C677T polymorphism and susceptibility to pre-eclampsia.

A number of studies have investigated the association between the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of pre-eclampsia (PE) in various populations and have delivered inconsistent results. Therefore, this meta-analysis of 36 case-control studies, comprising 4253 PE cases and 4950 controls, were assessed to evaluate a possible association. The pooled results showed that the MTHFR C677T polymorphism was significantly associated with PE (P=0.03, odds ratio (OR)=1.25, 95% confidence interval (CI)=1.02-1.54, for the additive comparison; P=0.04, OR=1.14, 95% CI=1.01-1.29, for the dominant genetic model). The results of the subgroup analysis showed that MTHFR 677T had the effect of increasing the PE risk for the recessive genetic model (P<0.0001, OR=1.76, 95% CI=1.33-2.33, P(heterogeneity)=0.28), the additive comparison (P=0.002, OR=2.09, 95% CI=1.31-3.31, P(heterogeneity)=0.08) and allele contrasts (P=0.03, OR=1.42, 95% CI=1.04-1.95, P(heterogeneity)=0.0001) in the Asians, while no evidence of an association between MTHFR C677T polymorphisms and PE was observed in the Caucasians. This meta-analysis suggests that the MTHFR C677T polymorphism is capable of causing PE susceptibility in the Asians but not in the Caucasians.