MTHFR and gestational diabetes: However, little is known if folic acid intake contributes to lower GDM risk in pregnant women with MTHFR C677T polymorphisms and moreover, if a pregnant woman with MTHFR 677 TT genotype was diagnosed with GDM, would higher folic acid intake be effective in terms of GDM relief, which was defined by negative OGTT follow-up test results.