Polycystic ovary syndrome (PCOS) is a condition in which the ovaries contain many cystic follicles that are associated with chronic anovulation and overproduction of androgens (male hormones). The cystic follicles exist presumably because the eggs are not expelled at the time of ovulation. Symptoms may include irregular menstrual periods, obesity, excessive growth of central body hair (hirsutism), and infertility. PCOS can also be associated with heart disease, hypertension, or diabetes. Also called Stein-Leventhal syndrome.