In essence, the Pill works by tricking the body into thinking it’s already pregnant. It does this by manipulating the normal hormonal feedback system. The end result is that the body doesn’t release the hormones necessary to stimulate the ovary to release an egg.

As a back-up, every other facet of the woman’s reproductive system is also altered. The uterine lining is prevented from producing a suitable environment for egg implantation, and the cervical fluid doesn’t develop the fertile quality necessary for sperm survival.