A patient with chronic anovulation and normal hormone levels tests positive on a progestin challenge test. What is the drug of choice for her infertility treatment?

The appropriate treatment for a patient with chronic anovulation who tests positive on a progestin challenge test is clomiphene citrate. This finding indicates that the patient has a functional hypothalamic-pituitary-ovarian axis, meaning that although ovulation is not occurring spontaneously, the patient still has the potential for ovulation when stimulated appropriately. Clomiphene citrate works by blocking estrogen receptors in the hypothalamus, which leads to increased secretion of gonadotropins (FSH and LH) from the pituitary gland. This stimulation promotes ovarian follicle development and can induce ovulation in women experiencing anovulation due to conditions such as polycystic ovary syndrome (PCOS).

The other medications listed are not the first-line choice for this scenario. Dehydroepiandrosterone sulfate is sometimes used in cases of poor ovarian reserve but does not directly induce ovulation. Bromocriptine is typically indicated in cases where there is hyperprolactinemia leading to anovulation, and human menopausal gonadotropin is generally reserved for cases where there is more significant disruption of the hormonal axis or if other treatments have failed. Thus, clomiphene citrate is the most appropriate first-line treatment