PCOS

Generally said to affect 5-15% of women of reproductive age (1), PCOS may in fact affect up to 20% of women if the 2003 Rotterdam criteria is used (2,3).

Polycystic ovarian syndrome (PCOS) is generally defined 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) (4).

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 (4).

Thyroid dysfunction, congenital adrenal hyperplasia, hyperprolactinaemia, androgen-secreting tumours and Cushing’s syndrome must to be excluded before making a diagnosis of PCOS (4).

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)
• hyperinsulinaemia increases ovarian androgen biosynthesis, both in vivo and in vitro (4)
  • decreases the hepatic production of sex hormone-binding globulin (SHBG)(4)
    • 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 (6)

Suggested differential diagnoses and screening tests (4)

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

Ovulatory dysfunction can still occur with regular cycles and if anovulation needs to be confirmed serum progesterone levels can be measured (12).

If irregular menstrual cycles are present a diagnosis of PCOS should be considered (2)

References:

1. Roos N et al. Risk of adverse pregnancy outcomes in women with polycystic ovary syndrome: population based cohort study. BMJ 2011 Oct 13:343.
2. Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group, authors. Revised 2003 consensus on diagnostic criteria and long-term health risks related to polycystic ovary syndrome. Fertil Steril. 2004;81:19-25.
3. Chiaffarino F et al. Prevalence of polycystic ovary syndrome in European countries and USA: A systematic review and meta-analysis.
   Eur J Obstet Gynecol Reprod Biol. 2022 Dec:279:159-170
4. Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. J. Clin Endocrinol Metab. 2023 Sep 18;108(10):2447-2469
5. RCOG. (2014) Long-term Consequences of Polycystic Ovary Syndrome (Green-top Guideline No. 33).
6. Dewailly D. et al. Definition and significance of polycystic ovarian morphology: a task force report from the androgen excess and polycystic ovary syndrome society. Hum Reprod Update. 2014;20(3):334-352