Abstract: Methylenetetrahydrofolate reductase (MTHFR) is a rate limiting enzyme involved in folate metabolism and DNA methylation, which participates in a variety of physiological and biochemical reactions. There are many types of MTHFR gene mutation, but C677T is the most studied and common type of mutation. The gene mutation can decrease enzymatic activity, thereby affecting processes of folate metabolism, DNA synthesis and methylation, which increases susceptibilities to the gene-related disease utimately. Due to the regional and ethnic differences in MTHFR C677T gene polymorphism, the same disease has different results in different regions and races. In recently years, more and more attention has been paid to gene polymorphisms and related diseases. Researches revealed that polymorphisms of MTHFR C677T gene can lead to hyperhomocysteinemia, resulting in embryonic development disorder and damage to vascular endothelium，which leads to recurrent abortion and hypertensive disorders of pregnancy, while the occurrence of gynecologic tumor may be mainly related to DNA methylation obstruction. This article presents an overview on advances in studies of MTHFR C677T gene polymorphisms in obstetrics and gynecology field.

Key words: Methylenetetrahydrofolate reductase (NADPH2);, Polymorphism, genetic, Folic acid;, Pregnancy complications, Genital neoplasms, female