Clinical Evidence Handbook
A Publication of BMJ Publishing Group
Polycystic Ovary Syndrome
Am Fam Physician. 2009 Sep 15;80(6):579-580.
Polycystic ovary syndrome (PCOS) is characterized by an accumulation of incompletely developed follicles in the ovaries due to anovulation, and is associated with increased ovarian androgen production. Clinical manifestations of PCOS include infrequent or absent menses; obesity; and signs of androgen excess, such as acne or seborrhea.
PCOS is diagnosed in up to 10 percent of women attending gynecology clinics, but the prevalence in the population as a whole is unclear.
PCOS has been associated with hirsutism, infertility, acne, insulin resistance, elevated serum luteinizing hormone (LH) levels, weight gain, type 2 diabetes, cardiovascular disease, and endometrial hyperplasia.
Metformin in selected patients (who have abnormal LH/follicle-stimulating hormone [FSH] ratios) may improve menstrual pattern and oligomenorrhea. The results of studies comparing metformin with placebo are conflicting for menstrual frequency and hirsutism. Metformin, alone or combined with cyproterone acetate/ethinyl estradiol (co-cyprindiol), may be more effective than cyproterone acetate/ethinyl estradiol alone at reducing hirsutism. Metformin combined with flutamide reduces hirsutism scores and improves menstrual frequency compared with placebo, but we do not know how the individual medications compare with each other.
Cyproterone acetate/ethinyl estradiol may reduce hirsutism, but increases the risk of venous thromboembolism compared with placebo.
Finasteride may reduce hirsutism compared with placebo, and seems as effective as spironolactone or cyproterone acetate/ethinyl estradiol. Finasteride plus cyproterone acetate/ethinyl estradiol may be more effective than cyproterone acetate/ethinyl estradiol alone at reducing hirsutism.
Flutamide, alone and in combination with metformin, may reduce hirsutism compared with placebo, but has been associated with adverse hepatic effects. Flutamide may reduce hirsutism compared with finasteride, but studies have had conflicting results. Flutamide and spironolactone seem equally effective at reducing hirsutism.
Combined treatment with flutamide plus cyproterone acetate/ethinyl estradiol may reduce the proportion of women with oligomenorrhea compared with flutamide alone.
We do not know whether weight loss improves clinical outcomes in women with PCOS.
We do not know whether ketoconazole or hair removal treatments are effective at reducing hirsutism compared with other treatments. Mechanical hair removal with certain types of lasers may be effective in the short term (six months), but longer-term effects are less clear.
What are the effects of treatments in women with polycystic ovary syndrome?
Likely to be beneficial
Finasteride (may be similarly effective in reducing hirsutism as spironolactone and cyproterone acetate/ethinyl estradiol)
Flutamide (may be similarly effective in reducing hirsutism as finasteride and spironolactone)
Metformin (improved menstrual pattern compared with placebo; reduced hirsutism compared with cyproterone acetate/ethinyl estradiol)
Spironolactone (may be similarly effective for reducing hirsutism as flutamide and finasteride)
Trade-off between benefits and harms
Cyproterone acetate/ethinyl estradiol (co-cyprindiol; reduced hirsutism but increased risk of venous thromboembolism)
Mechanical hair removal
Weight loss (interventions to achieve weight loss)
PCOS (Stein-Leventhal syndrome; sclerocystic ovarian disease) is by definition a syndrome for which there is no single criterion to confirm clinical diagnosis. PCOS is diagnosed when there is ultrasound evidence of polycystic ovaries or hyperandrogenism. PCOS is characterized by an accumulation of incompletely developed follicles in the ovaries due to anovulation, and is associated with increased ovarian androgen production. Clinical manifestations include infrequent or absent menses, obesity, and signs of androgen excess, which include acne or seborrhea. Women with PCOS commonly have insulin resistance, have elevated serum LH levels, and are at an increased risk of type 2 diabetes and cardiovascular events.
Incidence and Prevalence
PCOS is diagnosed in 4 to 10 percent of women attending gynecology clinics in resource-rich countries, but this figure may not reflect the true prevalence because there have been no specific population-based studies, and the criteria used for diagnosis are varied. An international consensus definition of PCOS defined a set of criteria used for diagnosis. Studies since then suggest a greater than 20 percent incidence and prevalence of PCOS in overweight and obese women.
The etiology of PCOS is unknown. Genetic factors may play a part, but the exact mechanisms are unclear. Two studies found some evidence of familial aggregation of hyperandrogenemia (with or without oligomenorrhea) in first-degree relatives of women with PCOS. In the first study, 22 percent of sisters of women with PCOS fulfilled diagnostic criteria for PCOS. In the second study, of the 78 mothers and 50 sisters evaluated clinically, 19 (24 percent) of the mothers and 16 (32 percent) of the sisters had PCOS.
The diagnosis excludes secondary causes, such as androgen-producing neoplasm, hyperprolactinemia, and adult-onset congenital adrenal hyperplasia. PCOS is characterized by irregular menstrual cycles, scanty or absent menses, multiple small cysts on the ovaries (polycystic ovaries), mild hirsutism, and infertility. Many women also have insulin resistance, acne, and weight gain. Until recently, there was no overall consensus on the criteria for diagnosing PCOS. In some studies, it has been diagnosed based on the ultrasound findings of polycystic ovaries rather than on clinical criteria. An international consensus definition of PCOS has now been published, which defines PCOS as having at least two of the following criteria: reduced or no ovulation; clinical or biochemical signs of excessive secretion of androgens; or polycystic ovaries (the presence of at least 12 follicles measuring 2 to 9 mm in diameter, an ovarian volume of more than 10 mL, or both).
There is some evidence that women with PCOS are at increased risk of developing type 2 diabetes and cardiovascular disorders secondary to hyperlipidemia, compared with women who do not have PCOS. However, although there is a higher risk of cardiovascular disorders, there is no apparent increase in risk of mortality. There is some evidence that women who have oligomenorrhea and amenorrhea are at increased risk of developing endometrial hyperplasia and, later, endometrial carcinoma.
editor's note: Cocyprindiol is not available in the United States.
search date: December 2007.
Adapted with permission from Cahill D. PCOS. Clin Evid Handbook. June 2009:620–621. Please visit http://www.clinicalevidence.bmj.com for full text and references.
This is one in a series of chapters excerpted from the Clinical Evidence Handbook, published by the BMJ Publishing Group, London, U.K. The medical information contained herein is the most accurate available at the date of publication. More updated and comprehensive information on this topic may be available in future print editions of the Clinical Evidence Handbook, as well as online at http://www.clinicalevidence.bmj.com (subscription required). Those who receive a complimentary print copy of the Clinical Evidence Handbook from United Health Foundation can gain complimentary online access by registering on the Web site using the ISBN number of their book.
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