Approach to ovulation induction

The approach to treating anovulation depends on the cause.

Individuals with premature ovarian insufficiency require prompt referral to a fertility specialist because assisted reproductive technology with a donor oocyte or embryo is generally required.

For individuals with a disorder of the hypothalamic–pituitary axis, first address underlying causes (eg low weight, systemic illness, stressors). Treat hyperprolactinaemia with dopamine agonists.

For individuals with PCOS, address diet and exercise first; also consider metformin (see PCOS and subfertility for more information).

If anovulation persists in individuals with a hypothalamic–pituitary disorder or PCOS, ovulation induction may be useful. This is the process of promoting the release of an oocyte from a single mature ovarian follicle¹. The oocyte can then be fertilised naturally, or with intrauterine insemination. Drugs to induce ovulation should only be used with specialist guidance or prescribed by a specialist, because there is a risk of multiple follicles developing; see Assessing for multiple follicles in ovulation induction.

Drugs to induce ovulation include aromatase inhibitors (eg letrozole), estrogen receptor antagonists (eg clomifene) and gonadotrophins (follicle stimulating hormone [FSH] with human chorionic gonadotrophin [hCG]). Letrozole and clomifene work by suppressing estrogenic feedback on the hypothalamus, so are unlikely to be effective in females with low serum estradiol. Gonadotrophins are preferred in this situation, or when letrozole and clomifene have been ineffective or cannot be used (eg due to patient concerns about adverse effects).