Would You Prescribe Clomiphene or Metformin to Treat Her Anovulatory Infertility?
PCOS and infertility are common problems affecting 6 and 8% of women of reproductive age, respectively (1, 2). Anovulation or oligo-ovulation is the cause of infertility in about 25% of cases (3). In turn, PCOS is the most common cause of anovulatory infertility (4). For women with PCOS and infertility and a normal BMI, the initial approach to induction of ovulation includes the choice of clomiphene or metformin. The ovulation-inducing properties of clomiphene and metformin reflect the underlying pathophysiology of PCOS, in which both reproductive axis abnormalities (increased GnRH pulse frequency and increased LH) (5) and metabolic derangements (insulin resistance, metabolic syndrome, excess visceral fat activity, and endothelial inflammation) (6) contribute to the anovulation and infertility. Clomiphene likely improves ovulation in women with PCOS by partially blocking estradiol negative feedback on FSH secretion, resulting in increased pituitary gonadotropin secretion (7). Metformin
