Evidence check: MTHFR in the context of fertility

The role of the MTHFR gene in fertility is controversial. Some observational studies suggest an association between certain MTHFR variants (e.g., C677T) and recurrent miscarriage, especially when homocysteine levels are elevated. However, the evidence is generally weak and insufficient to recommend routine screening. Guidelines such as those from the American College of Obstetricians and Gynecologists (ACOG) advise against routine MTHFR testing for fertility issues, as the predictive value is low and most carriers have no problems. A DNA test from MyBody-X can detect the relevant SNPs, but clinical utility remains limited. More important factors include age, lifestyle, hormonal status, and organic causes. Folic acid supplementation is generally recommended regardless of MTHFR status. The evidence level is therefore moderate: there is a plausible biological mechanism (homocysteine metabolism), but clinical relevance is uncertain. Caution is warranted to avoid false reassurance or unnecessary concern.