Unexplained Subfertility

Unexplained infertility is defined as failure to conceive after 12 or more months of unprotected intercourse in couples where ovulation, tubal patency, and semen parameters are all within normal limits. Trial eligibility requires that at least 70% of participants meet unexplained infertility criteria, or that outcomes are separately reported for an unexplained subgroup. Because the aetiology of unexplained infertility is undefined, treatment is empirical rather than targeted, creating uncertainty for patients and clinicians alike. The LUMO study targets couples with unexplained subfertility as its study population.