Montgomery Fertility Center
3202 Tower Oaks Boulevard
Rockville, MD 20852
Metformin Use In PCOS
Polycystic ovary syndrome (PCOS) is a common disorder caused by hormonal imbalance among women of reproductive age. Women with PCOS may have infrequent or prolonged menstrual periods or excess male hormone (androgen) levels.
Patients with PCOS may experience irregular menstrual periods, heavy periods, excess hair, acne, pelvic pain, and difficulty getting pregnant. It is often associated with the inability to ovulate, insulin resistance, and neuroendocrine disruption. Mantzoros et al. describes insulin resistance as ‘‘a state (of a cell, tissue, or organism) in which a greater than normal amount of insulin is required to elicit a quantitatively normal response’’ and maintain glucose levels within the normal range. Individuals with insulin resistance may be overtly diabetic or merely have insulin resistance detected by testing.
There are many endocrine pathways that can result in polycystic ovary syndrome. There is disruption in the cyclic growth and subsequent ovulation of oocytes in the ovary. Polycystic ovary syndrome is a complex topic. One of the medications used in the treatment of its associated infertility is metformin.
Metformin is an insulin-sensitizing agent that lowers blood glucose levels in hyperglycemic individuals but has no effect on glucose levels in normal subjects. Metformin reduces absorption of glucose uptake from the gastrointestinal tract, blocks liver glucose production, and increases insulin stimulated glucose uptake in the periphery.
Metformin has self-limited side effects that abate with continued use. The side-effects such as abdominal discomfort, nausea, and diarrhea may cause some weight loss.
It is used as an adjunct in the treatment of PCOS. The use of metformin alone is not associated with increases in pregnancy rates or live birth rates.
Pretreatment with metformin for at least three months followed by the addition of another ovulation-inducing drug such as Clomid or Letrozole, increases live-birth rates. For PCOS, Letrozole is the first line agent for ovulation induction in PCO patients. Metformin used while attempting pregnancy and stopped at the initiation of pregnancy does not affect the rate of miscarriage.
Metformin alone should not be used as first-line therapy for ovulation induction in women with PCOS, since ovulation induction agents such as Clomid or Letrozole are more effective. Clomid alone or letrozole alone are reasonable first-line agents for ovulation in women with PCOS. Combination therapy with Clomid may be beneficial in women who are resistant to Clomid alone.