Polycystic ovarian syndrome (PCOS), also known as Stein-Leventhal syndrome can develop in women as a result of having too many male hormones and not enough female hormones in their bodies. PCOS causes ovulation to become rare and/or irregular. This happens because PCOS develops benign cysts in the ovaries that impede healthy hormonal balance. Symptoms associated with PCOS include obesity, hair growth on the face, chest and lower abdomen, acne, infertility, irregular periods, skipped periods and either very light or extremely heavy menstrual flow.

Losing weight can often improve ovulation. Additionally, many women seek out the help of fertility medications or get a surgeon to remove the ovarian cysts, which can improve the body's hormonal balance and ovulation cycles considerably.