Polycystic Ovarian Syndrome (PCOS) is characterized by irregular ovulation and menses, obesity, insulin resistance, acne, and hirsutism (excessive hair growth). Impaired fertility is a prominent feature of PCOS. This is believed to result from elevated insulin levels that stimulate excess androgen production by the ovaries.

Biochemically, PCOS is associated with:

a raised LH:FSH ratio insulin resistance

hyperandrogenism (raised androstenedione levels and raised testosterone).

Rapid development of hirsutism is usually caused by an adrenal tumour. There are high testosterone or DHEA levels in the plasma.