Overview
Investigate both gamete contributors in parallel, identify treatable ovulatory and gonadal endocrine disorders, and refer promptly for monitored fertility treatment without offering hormones that impair sperm or create avoidable multiple pregnancy.
Endocrine infertility can result from failure to ovulate, deficient ovarian reserve, excess prolactin, thyroid disease, severe androgen excess, hypothalamic energy deficiency or testicular and pituitary failure. Age, semen quality, tubal patency, uterine disease and sexual function remain equally important. A diagnosis such as PCOS is not a complete fertility assessment.
Gonadotrophin patterns localise disease. Raised FSH with low sex steroid suggests primary gonadal failure; low or inappropriately normal gonadotrophins suggests hypothalamic-pituitary deficiency. In PCOS, androgen excess and irregular ovulation may occur with non-raised FSH. Male hypogonadotrophic hypogonadism is unusually amenable to hormonal induction of spermatogenesis, whereas testosterone replacement suppresses it.
The central decision is whether expectant conception remains reasonable, whether a reversible endocrine disorder should be treated first, or whether time-sensitive referral for ovulation induction, surgery, donor gametes or IVF is appropriate. Investigation and treatment should be inclusive of couples, single people, same-sex partners and trans or non-binary people according to organs, gametes, prior hormones and individual goals.