What role does FT3 play in Fruchtbarkeit?

FT3 (free triiodothyronine) is the biologically active form of thyroid hormone and plays a significant role in both female and male fertility. In women, FT3 influences menstrual cycle regulation, ovarian follicle development, oocyte quality, and endometrial receptivity. In men, FT3 can affect spermatogenesis and sperm motility. Thyroid dysfunction (hypo- or hyperthyroidism) is associated with menstrual irregularities, infertility, and increased miscarriage risk. However, the evidence for a direct causal role of FT3 alone – independent of TSH and FT4 – is limited. Most studies evaluate the entire thyroid profile. An isolated abnormal FT3 level without TSH/FT4 changes is rare and requires medical evaluation. Consumer lab tests measuring only FT3 provide no meaningful fertility assessment without context. The evidence for FT3 as a standalone fertility marker is moderate, not strong. Caveat: Do not self-medicate with thyroid hormones; proper medical diagnosis is essential.