Clomiphene citrate, commonly known as clomid, functions as a selective estrogen receptor modulator. By blocking estrogen receptors in the hypothalamus, it deceives the body into perceiving low estrogen levels, which in turn stimulates the pituitary gland to produce more follicle-stimulating hormone (FSH) and luteinizing hormone (LH). This increased production of FSH and LH promotes the growth and maturation of ovarian follicles, leading to ovulation. This makes clomid particularly effective for women with PCOS, who often experience irregular ovulation due to hormonal imbalances.
Clomid was commonly used in early protocols for ovarian stimulation and IVF, but saw decreased usage with the introduction of more effective GnRH agonists and antagonists in the 1980s.