How Does Metformin Work With Pcos?

PCOS (polycystic ovarian syndrome) is one of the leading causes of infertility. It affects 4 to 10 percent of females of childbearing age. Metformin is a prescription drug approved by the FDA for treatment of type 2 diabetes, but it is sometimes used off-label to treat women with PCOS.

Symptoms of PCOS

PCOS is caused by a hormonal imbalance. The ovaries of women with PCOS make too much of the male sex hormones, or androgens. Women's bodies require some androgens to function properly, but excess androgen levels can lead to infrequent periods, infertility, weight gain and unwanted facial hair. About half of women with PCOS also have too much insulin circulating in the bloodstream. Insulin also stimulates the release of androgen by the ovaries.

Results

Sixty percent of anovulatory (non-ovulating) women given metformin ovulated after taking the drug. Up to 25 percent of women who do not ovulate after taking the fertility drug clomiphene will ovulate when metformin is added to their drug regimen. By lowering the levels of insulin, metformin restores the hormonal balance needed for ovulation to occur.

Function

Metformin is a biguainide drug used to treat diabetes. The main action of metformin is reducing the amount of glucose (sugar) manufactured in the liver (gluconeogenesis). Metformin also slows the absorption of sugar from the intestines and makes the body more sensitive to insulin. All of these actions work together to lower blood sugar and prevent the release of excess insulin.

Insulin is a hormone that transports glucose, or sugar, from the bloodstream into the cells of the body. Cells require sugar for the energy they need to survive. Once the cells have the energy they need, any remaining insulin stimulates hunger and fat storage.

People with high insulin levels have a greater risk of developing type 2 diabetes. Metformin reduces the insulin levels in women with PCOS who also have high insulin levels and reduces their risk of developing diabetes later in life.

Side Effects

Women with PCOS who are not trying to get pregnant should be aware that metformin can trigger ovulation, so they may want to use birth control when the begin taking metformin. Metformin has not been approved for use during pregnancy or breast-feeding.

Metformin can cause a rare but serious condition called lactic acidosis. To lower the risk of developing lactic acidosis, people with kidney or liver problems should not take metformin. The most common side effects of metformin are upset stomach and diarrhea, but this often goes away with time.