Polycystic Ovarian Syndrome (PCOS)
Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:
-- The first section of this topic is shown below --
- Polycystic ovarian syndrome (PCOS) is a common endocrine disorder with heterogeneous manifestations that affects 6–10% of the U.S. population.
- Characterized by hyperandrogenism, insulin resistance, and anovulation, typically presenting as amenorrhea or oligomenorrhea
- Diagnostic clinical characteristics include menstrual dysfunction, infertility, hirsutism, acne, obesity, and metabolic syndrome.
- The ovaries are often polycystic on imaging.
- The etiology of PCOS is unknown but can be modified by lifestyle factors.
- System(s) affected: reproductive, endocrine/metabolic, skin/exocrine
- Synonym(s): Stein-Leventhal syndrome; polycystic ovary disease
- Condition may begin at puberty.
- Obesity may amplify PCOS, but it is not diagnostic.
- 20% of women with PCOS are not obese.
- Predisposes to and is associated with obesity, hypertension, diabetes, metabolic syndrome, hyperlipidemia, infertility, insulin-resistance syndrome, endometrial hyperplasia, and uterine cancer
- Incidence and prevalence are still highly debated due to a wide spectrum of diagnostic features: The National Institutes of Health (NIH) criteria require chronic anovulation and hyperandrogenism.
- The prevalence based on NIH criteria is 7% of reproductive age women.
- Predominant age: reproductive age
- Predominant sex: females only
Etiology and Pathophysiology
- Recent evidence points to a primary role for insulin resistance with hyperinsulinemia.
- Increased GnRH pulsations in the hypothalamus lead to increased production of LH with limited production of FSH.
- Hyperandrogenism: Ovaries are the main source of excess androgens (75% of circulating testosterone originates in the ovary). Polycystic ovaries have thickened thecal layers and overexpressed LH receptors, which cause excess androgen secretion.
- Ovarian follicles: Abnormal androgen signaling may account for abnormal folliculogenesis causing polycystic ovaries.
- Obesity results in compensatory hyperinsulinemia: Women with PCOS have insulin resistance similar to that in type 2 diabetes. Elevated levels of insulin decrease sex hormone–binding globulin (SHBG), increasing bioavailability of testosterone. Insulin may also act directly on adrenal glands, ovaries, and hypothalamus to enhance androgen production.
- Insulin resistance causes elevated insulin levels and the frequently associated metabolic syndrome or frank diabetes mellitus.
- Likely a combination of polygenic and environmental factors
- Implicated genes include DENND1A and THADA.
See “Commonly Associated Conditions”; cause and effect are difficult to extricate in this disorder.
None known; focus on early diagnosis and treatment to prevent long-term complications.
Commonly Associated Conditions
- Obstructive sleep apnea
- Diabetes mellitus
- Endometrial hyperplasia/carcinoma
- Fatty liver disease
- Mood disturbances and depression