Approximately 60-70 percent of women with Polycystic Ovary Syndrome (PCOS) exhibit menstrual dysfunction related to anovulation. The most common abnormalities are infrequent periods (oligomenorrhoea) and absence of period (amenorrhoea). Frequent and prolonged periods (polymenorrhoea) are very uncommon (less than two percent). One quarter of patients have regular periods.
They are either markers of hyperandrogenism (excessive production of male hormones) or insulin resistance.
The difficulty in conceiving is mainly due to chronic anovulation. Polycystic Ovary Syndrome (PCOS) accounts for approximately 75 percent of anovulatory subfertility.
Obesity is often associated with PCOS (30-70 percent), but many patients with PCOS are of normal weight.