Polycystic ovary syndrome

Last updated: September 6, 2023

Summarytoggle arrow icon

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. It is characterized by hyperandrogenism (which primarily manifests as hirsutism, acne, and, occasionally, virilization), oligoovulation/anovulation, and/or the presence of polycystic ovaries. The diagnosis involves a complete history and physical examination to evaluate for ovulatory dysfunction and clinical signs of hyperandrogenism. Laboratory tests are performed to confirm biochemical hyperandrogenism and exclude other conditions with a potentially similar clinical picture (e.g., congenital adrenal hyperplasia). Ultrasound may be performed in adults to identify cystic follicles and assess ovarian volume but is not required for diagnosis if ovulatory dysfunction and hyperandrogenism are present. Management consists of lifestyle modifications combined with specific treatment, which is tailored to the patient's reproductive goals. In women who do not wish to conceive, combined oral contraceptive pills are indicated to regulate menses and treat hyperandrogenism. For women who wish to conceive, the goal of treatment is to induce ovulation (e.g., with letrozole). Women with PCOS are twice as likely to develop metabolic syndrome, which is associated with obesity, insulin resistance, hypercholesterolemia, and an increased risk of endometrial cancer. Therefore, all patients should be screened for comorbidities and receive specific treatment for these when necessary.

Epidemiologytoggle arrow icon

  • Prevalence: 6–12% of women in their reproductive years in the US [1]

Epidemiological data refers to the US, unless otherwise specified.

Pathophysiologytoggle arrow icon

Hyperandrogenism in women is most commonly caused by PCOS.

Clinical featurestoggle arrow icon

Onset of symptoms typically occurs during adolescence.

Voice change may occur in severe forms of PCOS. However, it typically suggests a different underlying cause of hyperandrogenism.

Pathologytoggle arrow icon

Macroscopic appearance

  • Multiple, brown cysts arranged in a circular pattern in the subcapsular region of the ovary
  • Cysts are relatively small and of approximately the same size.

Microscopic appearance

Differential diagnosestoggle arrow icon

Hyperandrogenism [5]


  • Definition: a state of excess androgen levels that causes symptoms such as growth of facial hair, deepening of the voice, and male-pattern baldness
  • For more information about physiological causes of hyperandrogenism, see “Pregnancy.”
Differential diagnosis of hyperandrogenism in female individuals
Incidence Onset Characteristic finding
  • Most common (75–80% of cases)
  • Peripubertal
Nonclassic CAH
  • Common
  • Peripubertal
  • ↑ 17-Hydroxyprogesterone
  • Congenital
  • Ambiguous genitalia
Cushing disease
  • Any time
  • Any time
  • Uncommon
  • Any time
Androgen-secreting tumor (e.g., Sertoli-Leydig cell tumor, adrenal)
  • Primarily affects women 30–40 years of age
  • 3rd decade of life (mean age at diagnosis usually 40–45 years)
Ovarian hyperthecosis
  • Rare
Placental aromatase deficiency
  • Rare
  • Affected individuals: congenital
  • Maternal: during pregnancy
Drug-induced (e.g., exogenous steroid and androgen intake)
  • N/A
  • N/A

Clinical features of hyperandrogenism

Diagnostics of hyperandrogenism


The differential diagnoses listed here are not exhaustive.

Diagnosticstoggle arrow icon

Approach [6][7][8]

Early diagnosis is essential, as PCOS is associated with many conditions, including metabolic dysfunction and impaired fertility. It also has a significant impact on a woman's emotional well-being and quality of life.

Rotterdam criteria [6][9][10]

PCOS is diagnosed in adults based on the presence of at least two of the following criteria, after other endocrinological conditions, e.g., thyroid disease, hyperprolactinemia, have been excluded.

Diagnosing PCOS in adolescents is complex because PCOS symptoms overlap with normal pubertal changes. For this reason, the 2015 Pediatric Endocrine Society consensus does not endorse the use of ultrasound in adolescents to evaluate PCOS. [11]

Laboratory studies [6][9][10]

A clinical picture of hyperandrogenism fulfills a diagnostic criterion of PCOS, even if serum androgen levels are normal.

An elevated LH (with LH:FSH ratio > 2:1) is a characteristic finding in most patients with PCOS but not necessary for diagnosis.

Ultrasound [10]

  • Parameters: An experienced clinician should assess the ovarian volume and, when feasible, the number and volume of follicles. [10]
  • Modalities
    • Transvaginal (preferred; use if acceptable to patient): offers the best visualization of ovarian follicles
    • Transabdominal: should focus on measuring ovarian volume

Identification of cystic follicles is not mandatory to diagnose PCOS.

Evaluate for comorbidities [6][9][10]

Patients with PCOS are at risk of serious comorbidities, even at a young age. It is important to screen for these at the first visit and at regular intervals.

  • Metabolic screening and monitoring
    • Measure weight, height, and waist circumference; calculate BMI. Measure at baseline and repeat every 6–12 months.
    • For patients with elevated BMI: Obtain a fasting lipid profile and screen for symptoms of obstructive sleep apnea.
    • Check blood pressure: Obtain at baseline and then at least once a year; measure more frequently based on individual risk.
    • Assess glycemic status : Obtain at baseline and repeat every 1–3 years, depending on individual risk.
  • Mental health and quality of life: Screen for anxiety, depression, and psychosexual dysfunction.

Women with PCOS are at least twice as likely to have metabolic syndrome as women without PCOS. [6]

Women with PCOS are also at increased risk for endometrial cancer. Screening is not routinely recommended, but clinicians should maintain a high index of suspicion and conduct a transvaginal ultrasound and/or endometrial biopsy if there are suggestive features (e.g., thickened endometrium, abnormal vaginal bleeding). [10]

Treatmenttoggle arrow icon

Approach [6][8][9][10]

  • Recommendations for all patients
    • Encourage exercise and healthy eating (e.g. caloric restriction), and consider behavioral strategies and modifications (e.g., setting goals, eating more slowly). [6][7]
    • Target BMI < 25 kg/m2 (can reduce estrone production in the adipose tissue)
    • Screen for comorbidities and provide specific treatment.
  • Tailor additional therapeutic interventions based on:

Features associated with PCOS (e.g., obesity, hyperandrogenism, difficulties conceiving) can have a negative psychosocial impact. If symptoms of anxiety and/or depression are identified, further mental health assessment and a referral to a mental health professional should be offered to the patient.

Patients not planning to conceive [6][8][9][10]

For patients who do not wish to conceive, the therapeutic goals are to control menstrual irregularities and hyperandrogenism, treat comorbidities, and improve quality of life.

Patients planning to conceive [6][9][10]

The goals of treatment for patients who wish to conceive are management of comorbidities (e.g., weight loss for overweight or obese patients) and induction of ovulation.

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Referencestoggle arrow icon

  1. PCOS (Polycystic Ovary Syndrome) and Diabetes. Updated: March 24, 2020. Accessed: April 30, 2020.
  2. American College of Obstetricians and Gynecologists' Committee on Practice Bulletins—Gynecology.. ACOG Practice Bulletin No. 194: Polycystic Ovary Syndrome.. Obstet Gynecol. 2018; 131 (6): p.e157-e171.doi: 10.1097/AOG.0000000000002656 . | Open in Read by QxMD
  3. Phiske M. An approach to acanthosis nigricans. Indian Dermatol Online J. 2014; 5 (3): p.239.doi: 10.4103/2229-5178.137765 . | Open in Read by QxMD
  4. Strain G, Zumoff B, Rosner W, Pi-Sunyer X. The relationship between serum levels of insulin and sex hormone-binding globulin in men: the effect of weight loss.. J Clin Endocrinol Metab. 1994; 79 (4): p.1173-6.doi: 10.1210/jcem.79.4.7962291 . | Open in Read by QxMD
  5. Hoeger KM, Dokras A, Piltonen T. Update on PCOS: Consequences, Challenges, and Guiding Treatment. The Journal of Clinical Endocrinology & Metabolism. 2020; 106 (3): p.e1071-e1083.doi: 10.1210/clinem/dgaa839 . | Open in Read by QxMD
  6. Teede HJ, Misso ML, Costello MF, et al. Recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Fertil Steril. 2018; 110 (3): p.364-379.doi: 10.1016/j.fertnstert.2018.05.004 . | Open in Read by QxMD
  7. Williams T, Mortada R, Porter S. Diagnosis and Treatment of Polycystic Ovary Syndrome.. Am Fam Physician. 2016; 94 (2): p.106-13.
  8. Legro RS, Arslanian SA, Ehrmann DA, et al. Diagnosis and treatment of polycystic ovary syndrome: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2013; 98 (12): p.4565-4592.doi: 10.1210/jc.2013-2350 . | Open in Read by QxMD
  9. Teede H, Misso M, Costello M, et al. International evidence-based guideline for the assessment and management of polycystic ovary syndrome. . 2018.doi: 10.1016/j.fertnstert.2018.05.004 . | Open in Read by QxMD
  10. EBERSOLE AM, BONNY AE. Diagnosis and Treatment of Polycystic Ovary Syndrome in Adolescent Females. Clinical Obstetrics & Gynecology. 2020; 63 (3): p.544-552.doi: 10.1097/grf.0000000000000538 . | Open in Read by QxMD
  11. $Screening and Management of the Hyperandrogenic Adolescent.
  12. Franik S, Eltrop SM, Kremer JA, Kiesel L, Farquhar C. Aromatase inhibitors (letrozole) for subfertile women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews. 2018.doi: 10.1002/14651858.cd010287.pub3 . | Open in Read by QxMD
  13. Yin W, Falconer H, Yin L, Xu L, Ye W. Association Between Polycystic Ovary Syndrome and Cancer Risk. JAMA Oncology. 2019; 5 (1): p.106.doi: 10.1001/jamaoncol.2018.5188 . | Open in Read by QxMD

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