How does the birth control pill work?

Birth Control pills work by giving your body additional estrogen and progesterone, at different amounts during the month. This increase in estrogen and progesterone works via a negative feedback loop; in other Words, it tells your body that there is a lot of estrogen and progesterone and therefore it needs to shut off the pathways that produce that estrogen and progesterone. To do this, the body lowers the amount of another hormone, FSH. This hormone, also known as follicle-stimulating hormone, not only affects the release of estrogen and progesterone, but also is necessary for follicle development. Birth control pills decrease the amount of FSH, making it impossible for your follicles to develop. Consequently, these follicles can never mature and release the egg.