What is the effect of oral contraceptive pills on women with polycystic ovarian syndrome?

This paper studied the various effects of oral contraceptive pills on women with polycystic ovarian syndrome. 

Women with polycystic ovarian syndrome often have reduced fertility and exhibit male sex characteristics. Polycystic ovarian syndrom occurs when a womans hormones are out of balance, leading to enlarged ovaries that contain small collections of fluids (cysts). Additionally, these women are at greater risk of diabetes and cardiovascular disease.

With regards to treatment,  oral contraceptive pills are given to women who do not wish to conceive. Oral contraceptive pills prevent pregnancy and reduce levels of male sex hormones. However, the effect of oral contraceptive pills is not clear, with conflicting results in research.  

1,297 women with polycystic ovarian syndrome were analyzed. These patients were divided into 3 groups. The first group had never before used oral contraceptive pills, the second group were currently using oral contraceptive pills and the third group had previously taken oral contraceptive pills.

Patients who were currently taking the pills had a decreased average ovarian volume (volume is increased in women with polycystic ovarian syndrome) compared to patients who had never taken pills. Indicators of ovarian reserve (the remaining egg supply in the ovaries) were similar in patients who had never taken pills and patients who were currently taking pills. Indicators of ovarian reserve were higher in patients who had previously taken pills than patients who were currently taking pills and patients who had never taken pills.

Patients who were currently taking the pills were less likely to have excess levels of androgen (a male sex hormone) than patients who had never taken the pills. Patients who had previously taken the pills also had a lower average level of testosterone (a male sex hormone) compared to patients who had never taken the pills.

Levels of fat in the body were similar among the three groups of patients. 

The authors concluded that the use of oral contraceptive pills led to less severe symptoms of polycystic ovarian syndrome and is not associated with long-term health risks.