How Birth control Pills Work

Most birth control pills are "combination pills" containing a mix of the hormones estrogen and progesterone to prevent the release of an egg during the monthly cycle. A woman cannot get pregnant if she doesn't ovulate because there is no egg to be fertilized.

The better you are about taking your pill every day and starting your pill packs on time, the better the pill will work. You can use our birth control app to remind

Birth Control Pills

Birth control pills work by emitting naturally-occurring hormones estrogen and progestin to prevent pregnancy. These hormones stop sperm from fertilizing an egg by stopping ovulation. Ovulation occurs when an ovary releases an egg, making it available for sperm to fertilize. The hormones in the pill also thicken cervix mucus, meaning it is more difficult for the sperm to get to the egg.

Types of Birth Control Pills

Birth control pills come in a variety of shapes and sizes, but there are two main types:

  • Combination pills and progestin-only pills. Combination pills get their name as they combine two hormones, estrogen and progestin, in order to prevent pregnancy. The amount of each hormone and the balance varies from brand to brand.
  • Progestin-only pills, meaning they contain no estrogen, are sometimes called the mini pill birth control. They also prevent pregnancy and for some women with estrogen sensitivity, they can be helpful in reducing certain side effects.

Birth control pills also work with different cycle lengths. The main types are 21-day packs, 28-day packs, and 91-day packs. The days in the cycle determine when you will get your period.

For the 21-day pack, you take pills for 21 days (three weeks), and get your period during the fourth week. There are still pills to take in the fourth week, but they are hormone-free and are just used to keep your habit of taking the pill every day.

The pills may contain iron or other supplements that help keep you healthy and are often referred to as reminder pills or “placebo” pills. 28-day packs work the same except you take pills for 28 days (four weeks) and get your period during the week after. 91-day packs means you will only get your period every three months or 12 weeks.

Some common birth control pill brands include Yaz, Yasmin, and Ortho Tri-Cyclen. A medical provider can prescribe these pills based on what’s best for the patient and their needs, but no matter the brand or hormone level, all help prevent pregnancy.