Between 40% and 85% of women with Polycystic Ovary Syndrome (PCOS) are overweight or obese and obesity is closely linked to the development of PCOS. Although it is well established that obesity increases the severity of the clinical features of PCOS, data regarding the prevalence of PCOS in obese women and the change in body weight in women with PCOS over time are scares. In a prevalence study it was investigated whether obesity increases the risk of PCOS in the general population and they demonstrated that the prevalence rate of PCOS in underweight, normal-weight, overweight, and obese women were 8.2, 9.8, 9.9, and 9.0%, respectively, similar to that observed in the general population. These results suggest that the risk of PCOS is only minimally increased with obesity. On the other hand, in a Spanish prevalence study among overweight and obese subjects, they demonstrated a 28.3% prevalence of PCOS, which is markedly higher compared with the 5.5% prevalence of PCOS in lean women in Spain.

First the investigators aim to estimate the prevalence/probability of PCOS among obese, premenopausal women (between 18 and 50 years) with no symptoms of classic menopausal symptoms in Sweden. Secondly, to elucidate whether women diagnosed with PCOS respond to standard weight reduction regime to the same extent as women without PCOS.

Inclusion Criteria:

PCOS diagnostic criteria should be the presence of both clinical and/or biochemical hyperandrogenism and/or oligo-/amenorrhea and/or polycystic ovaries (PCO).

Exclusion Criteria:

1. Exclusion of other endocrine disorders such as hyperprolactinemia (s-prolactin < 27µg/L), nonclassic congenital adrenal hyperplasia (17-hydroxyprogesterone < 3nmol/L), and androgen secreting tumors.
2. Pregnancy or breastfeeding the last 6 months.
3. Any sign of climacteric symptoms.
4. Language barrier or disabled person with reduced ability to understand information.
5. Oral contraceptives and insulin sensitizing agents is commonly used among women with PCOS since it may interfere with hormone profile. As the prevalence of PCOS can be assumed to be increased among women using oral contraceptives and insulin sensitizing agents, they are included but analyzed separately.

All obese women between 18 and 50 years referred to a weight reduction treatment program at the Sahlgrenska Obesity Center at Sahlgrenska University hospital will, after oral and written informed consent, be screened for the diagnosis of PCOS according to NIH or Rotterdam diagnostic criteria depending on the availability of ultrasonography.