Overview of menstrual disturbance and polycystic ovary syndrome

Many individuals with polycystic ovary syndrome (PCOS) have anovulatory cycles resulting in menstrual disturbance, including:

• irregular menstrual cycles of unusual length or variability
• oligomenorrhoea or amenorrhoea

Prolonged estrogenic stimulation of the endometrium during anovulatory cycles, without progestogen-induced shedding, causes endometrial thickening. This can result in heavy bleeding when menstruation does occur, and increases the risk of endometrial cancer 2-to 6-fold. Fertility is reduced in individuals with PCOS who have menstrual disturbance, but conception can occur even if menstruation occurs only occasionally; see PCOS and subfertility.

In those not wishing to conceive, menstrual regulation aims to control bleeding and provide protection from estrogen-induced endometrial cancer. Investigate heavy menstrual bleeding that persists despite 6 months of therapy to exclude endometrial cancer. Investigate earlier if there are additional features that increase cancer risk.