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PCOS

The cause of PCOS, or polycystic ovary syndrome, is multifactorial and not well-understood. Women with PCOS often have higher than normal levels of luteinizing hormone (LH) and androgens that impact the normal function of the ovaries. While multiple small follicles develop in the ovary, none are able to grow in size enough to become the dominant follicle and trigger ovulation. This leads to an imbalance of LH, follicle stimulating hormone, estrogen, and progesterone. Without ovulation, unopposed estrogen can lead to endometrial hyperplasia, or overgrowth of tissue in the uterus. This endometrial overgrowth is more likely to become cancerous than normal endometrial tissue. Thus, although the data varies, it is generally agreed upon by most gynecological societies that due to the unopposed estrogen, women with PCOS are at higher risk for endometrial cancer.

To reduce the risk of endometrial cancer, it is often recommended that women with PCOS who do not desire pregnancy take hormonal contraceptives to prevent the effects of unopposed estrogen. Both COCPs and progestin-only methods are recommended. It is the progestin component of COCPs that protects the endometrium from hyperplasia, and thus reduces a woman with PCOS's endometrial cancer risk. COCPs are preferred to progestin-only methods in women who also have uncontrolled acne, symptoms of hirsutism, and androgenic alopecia, because COCPs can help treat these symptoms.