Even though the hormonal imbalance that produces the symptoms of PCOS is becoming better understood, the disorder's actual cause is unknown.

What are the symptoms?

Symptoms of PCOS may first appear around the time of puberty. But usually they do not become noticeable until the early 20s. The most common symptoms are excessive hair growth (hirsutism), especially in areas where such growth is common to men, such as the chin and chest; irregular periods; PMS symptoms; excessive weight gain; acne; polycystic ovaries (enlarged ovaries with follicular cysts); male pattern hair thinning; acanthosis nigricans (a darkening of the skin around the areas of the neck, arms, breasts or thighs) and skin tags (small pieces of excess skin).

Symptoms of PCOS vary. Some women have just mild acne, whereas others have severe acne, facial hair growth and hair loss from the scalp. Many women do not show any visible signs of the syndrome.

How is PCOS diagnosed?

There is no single test to diagnose PCOS, which makes diagnosis difficult. However, the American Society for Reproductive Medicine and European Society of Human Reproduction and Embryology have agreed on guidelines for PCOS diagnosis. To be diagnosed with PCOS, a woman must exhibit two of the following: irregular or absent ovulation, elevated levels of androgens (male hormones), or polycystic ovaries diagnosed by ultrasound.