The number of studies with high risk of disease risk (RR > 2) resulted from MTHFR polymorphisms, which are greater in this meta-analysis of CHD condition than in previous meta-analyses of pregnant women with hypertensive diseases (15/71 studies, 21.1% of included studies for MTHFR 677; 2/11 studies, 18.2% of the included studies for MTHFR 1298) [23] and Alzheimer’s diseases (8/43, 18.6% of the studies for MTHFR 677) [38]. Here, MTHFR is linked to Alzheimer disease.