Polycystic Ovarian Syndrome

Revised 2003 criteria for diagnosis of PCOS

  • Clinical diagnosis of oligomenorrhoea or amenorrhoea: menstrual cycles longer than 35 days or fewer than 10 periods per year
  • Clinical (hirsutism, acne, androgen alopecia) or biochemical evidence of hyperandrogenism
  • Polycystic ovaries on USS:
    • 12 or more follicles per ovary, each measuring 2-9mm in diameter
    • ovarian volume >10ml
    • one polycystic ovary is sufficient

Differential diagnosis


Assessment can use the Ferriman Galwey score.

The primary driver of ovarian androgens is LH, which can be suppressed with a combined OCP. Efficacy depends on the dose of ethinylestradiol and the androgenic properties of the progestogen:

Treatments and efficacy (from Koulouri & Conway 2008)
Drug Reduction in FG score Comments
Flutamide 41% Liver toxicity, teratogenicity, use only with reliable contraception
Spironolactone 38% Menorrhagia or irregular menses, due to oestrogenic properties
Also potentially teratogenic
Cyproterone acetate 36% Weight gain, depression and headache
Potentially teratogenic, usually combined in Dianette
Thiazolidinediones 31%  
OCP 27%  
Finasteride 21% Blocks intracellular conversion of testosterone to DHT
Different mode of action means can be combined with other agents
Potentially teratogenic, use only with reliable contraception
Metformin 19%  
GnRH agonists   In the most severe cases
Profound oestrogen deficiency results, therefore used as "block and replace" with progestogen if intact uterus

Some quick comments about assisted reproduction from Richard Anderson (not specific to PCOS). Homburg (Hum Rep 2005) - 73% ovulation, 36% pregnancy, 10% multiple preg, 20% miscarriage, 25% single live birth with clomiphene? Typically start at 50-150mg/d x 5 d at start of cycle. Then FSH if no pregnancy after ovulation x 6. FSH treatment: 80-100% ovulation, 70% preg, 60% live birth.