How does Clomid (clomiphene) work to get someone pregnant?

Blocks estrogen. Clomiphene blocks estrogen receptors in the pituitary gland, which results in an increase in natural gonadotropins (fsh and lh). Fsh stimulates maturation of a follicle in the ovary.
Estrogen receptor. Clomid (clomiphene) blocks the estrogen receptors in the brain. The brain in turn releases hormones that stimulate the ovaries to produce eggs.