Is Folsäure useful for fertility?

Folic acid (vitamin B9) is critical for cell division and DNA synthesis, especially in early pregnancy. The standard recommendation of 400–800 µg/day for women planning pregnancy strongly reduces the risk of neural tube defects (strong evidence). Whether folic acid improves fertility in terms of faster conception is less clear. Some studies suggest benefits in women with MTHFR variants (e.g., rs1801133) or PCOS, but randomized controlled trials show no consistent effect on conception rates. High doses (>1 mg) can mask vitamin B12 deficiency and should only be taken under medical supervision. Genetic testing for MTHFR can provide clues but is not necessary for the general recommendation. Bottom line: folic acid is essential for a healthy pregnancy but not a direct fertility booster. The evidence for improved fertility is moderate and based mainly on observational studies.