Causes of anovulatory infertility
In approximately 10 to 20% of infertile couples, infertility is largely due to lack of ovulation. Anovulation is suggested by irregular menstrual cycles (less than 24 days or longer than 38 days) or amenorrhoea (absent bleeding for more than 90 days for a female with regular cycles, or more than 6 months for a female with irregular cycles).
Polycystic ovary syndrome (PCOS) is the most common cause of anovulation; it typically presents with irregular menstrual cycles.
Anovulation presenting with amenorrhoea may be related to:
- functional hypothalamic amenorrhoea (eg due to stress, excessive exercise, systemic illness, eating disorders or very low body weight)
- pituitary disorders (including prolactinoma and premature ovarian insufficiency or premature menopause)
- other endocrine causes of secondary amenorrhoea, which are rarer.
Exclude pregnancy as part of the assessment of anovulation.
The cause of anovulation should be determined before starting ovulation induction; the underlying disorders may have implications for general health, as well as fertility.
Ensure timely referrals for ovulation induction to maximise the likelihood of specialist treatment succeeding.