Insulin resistance is diagnosed in a subset of women who have polycystic ovarian syndrome, or PCOS, a common cause of infertility. In this group of women, insulin resistance is believed to play a crucial role in causing hormonal imbalances leading to abnormal ovarian function, irregular periods, problems ovulating and infertility.
Significance
Insulin resistance is an abnormal metabolic condition that is associated with diabetes and some causes of infertility. PCOS is one cause of infertility that often, but not always, has insulin resistance as a key feature. Insulin resistance results in high circulating levels of insulin, which in turn promote excessive production of androgens. High levels of male hormones or androgens are responsible for many of the infertility symptoms of PCOS.
Excess Androgens
When girls and women are exposed to high levels of androgens, they may develop physical features normally associated with men, including male pattern hair growth and excessive acne. Other signs of virilization caused by excessive androgens include deepening of the voice, decreased breast size, fat deposition more localized to the abdomen instead of the breast and hips, coarse hair growth on the chest, belly and face and, rarely, enlargement of the clitoris. High androgen levels are believed to be responsible for other ovarian changes, including enlarged ovaries with many small ovarian cysts that fail to ovulate, resulting in irregular periods and infertility.
Metabolic Features
Because insulin resistance is often a feature of PCOS, diagnosis of PCOS often involves looking for signs of metabolic syndromes more commonly associated with insulin-resistant diabetes, including excessive weight gain, obesity, high body mass index, or BMI, high cholesterol and high blood pressure.
Treatment
PCOS with underlying insulin resistance can be treated by a combination of medications to reduce high insulin levels and a diet and weight loss program to normalize body weight and composition. Metformin or generic glucophage are medications traditionally prescribed for diabetics to increase cell sensitivity to insulin, normalizing circulating insulin levels. Using Metformin to restore normal insulin levels can be effective in some women with PCOS to reverse the effects of syndrome and improve fertility.
Expert Insight
The molecular pathways by which insulin resistance and high androgen levels affect the ovaries are not fully understood, and studies to determine the best treatments for PCOS are still being undertaken. Some studies are looking for treatments that do not rely on Metformin to reduce insulin levels. At least one NIH supported clinical trial, "Treatment of Hyperandrogenism Vs. Insulin Resistance in Infertile Polycystic Ovary Syndrome (PCOS) Women (OWL-PCOS)," is recruiting patients to test whether treating high androgen levels using birth control pills or treating insulin resistance by reducing obesity through dietary and lifestyle changes is most effective.
