oral contraceptive

The oral contraceptive is the daily pill taken to prevent pregnancy. Its core idea is to gently fool the body into thinking it has already ovulated this cycle, so that no egg is released. By supplying steady doses of sex hormones, it overrides the natural hormonal surge that would normally trigger ovulation.

There are two main kinds. The combined pill contains both an estrogen and a progestin; the progestin-only pill (the "mini-pill") contains just a progestin. Both work mainly by suppressing the release of the brain's gonadotropins (LH and FSH), which prevents the surge that triggers ovulation; they also thicken cervical mucus so sperm cannot pass and thin the uterine lining. The combined pill is the more reliable ovulation-blocker, while progestin-only pills lean more on the mucus and lining effects.

Taken correctly they are highly effective, and they bring side benefits such as lighter, more predictable periods. The key caveat lies with the estrogen component: combined pills modestly raise the risk of venous blood clots and, in some users, stroke and heart attack, so they are avoided in smokers over 35, those with migraine with aura, or a history of clots. Progestin-only options sidestep most of that estrogen risk and suit those for whom estrogen is unsafe.