What role does Homocystein play in Fruchtbarkeit?

Homocysteine is a sulfur-containing amino acid produced during methionine metabolism. Elevated homocysteine levels (hyperhomocysteinemia) have been associated with fertility issues, but the evidence is largely observational and not sufficient for causal claims. In women, links to recurrent pregnancy loss, preeclampsia, and neural tube defects are discussed, mediated by oxidative stress, endothelial dysfunction, and impaired placental function. In men, studies suggest reduced sperm quality (motility, morphology, DNA integrity) with higher homocysteine. Regulation involves B vitamins (folate, B12, B6) and genetic variants like MTHFR C677T. However, randomized trials show limited fertility benefit from vitamin supplementation unless a deficiency is present. DNA tests for MTHFR variants have low predictive value for fertility; measured blood homocysteine is more clinically actionable. The evidence level is moderate – many association studies exist but few high-quality intervention trials. Lowering homocysteine without medical evaluation is not recommended.