PCOS

Last edited 09/2022 and last reviewed 09/2022

In the UK, up to 33% of women have polycystic ovaries (i.e. 10 or more follicles per ovary detected on ultrasound).

Of these, an estimated 33% have polycystic ovarian syndrome (PCOS), generally defined in the UK as polycystic ovaries together with one or more characteristic features (hirsutism, acne, male-pattern baldness, amenorrhoea or oligomenorrhoea, or raised serum concentrations of testosterone and/or luteinising hormone) .

In polycystic ovarian syndrome the associated metabolic abnormalities (abnormal serum lipid concentrations and insulin resistance) also put some women at an increased risk of developing diabetes mellitus (1)

NICHD (1990) Diagnostic Criteria for PCOS is:
Clinical Hyperandrogenism (Ferriman-Gallwey Score >8) or Biochemical Hyperandrogenism (Elevated Total/Free Testosterone) AND
Oligomenorrhea (Less Than 6-9 Menses per Year) or Oligo-Ovulation AND
Polycystic Ovaries on Ultrasound (>= 12 Antral Follicles in One Ovary or Ovarian Volume >= 10 cm3)

 

Rotterdam (2003) Diagnostic criteria for PCOS - two out of three of:
Clinical Hyperandrogenism (Ferriman-Gallwey Score >8) or Biochemical Hyperandrogenism (Elevated Total/Free Testosterone) OR
Oligomenorrhea (Less Than 6-9 Menses per Year) or Oligo-Ovulation OR
Polycystic Ovaries on Ultrasound (>= 12 Antral Follicles in One Ovary or Ovarian Volume >= 10 cm3)

 

AE-PCOS Society (2009) Diagnostic Criteria for PCOS is:
Clinical Hyperandrogenism (Ferriman-Gallwey Score >8) or Biochemical Hyperandrogenism (Elevated Total/Free Testosterone) PLUS Either of:
Oligomenorrhea (Less Than 6-9 Menses per Year) or Oligo-Ovulation OR
Polycystic Ovaries on Ultrasound (>= 12 Antral Follicles in One Ovary or Ovarian Volume >= 10 cm3)

 

Thyroid dysfunction, congenital adrenal hyperplasia, hyperprolactinaemia, androgen-secreting tumours and Cushing’s syndrome must to be excluded before making a diagnosis of PCOS (1).

Although the primary aetiology of PCOS is unknown

  • insulin resistance with compensatory hyperinsulinaemia is a prominent feature of the syndrome and seems to play an important physiopathological role in hyperandrogenism, in both lean and obese women with PCOS (5,6)
  • hyperinsulinaemia increases ovarian androgen biosynthesis, both in vivo and in vitro (7,8)
    • decreases the hepatic production of sex hormone-binding globulin (SHBG)(9)
      • leading to increased bioavailability of free androgens
  • PCOS task force recommends to utilize either follicle number per ovary (>=25) when a sophisticated US transducer >= 8MHz is available or, otherwise, an ovarian volume of >=10 ml to define PCOS morphology (10)

Suggested differential diagnoses and screening tests (11)

  • pregnancy - pregnancy test
  • hypothyroidism - TSH
  • hyperprolactinemia - PRL
  • Cushing's syndrome - 24-hour urine free cortisol
  • late-onset CAH (congenital adrenal hyperplasia) - 17-hydroxyprogesterone
  • ovarian tumor - total testosterone
  • hyperthecosis - total testosterone
  • adrenal tumor - dehydroepiandrosterone sulfate (DHEAS)

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