The oral contraceptive pill, commonly known as "the pill," is a hormone-based method of preventing pregnancy. It can also help resolve irregular menstruation, painful or heavy periods, endometriosis, acne, and premenstrual syndrome (PMS).
Birth control pills work by preventing ovulation. No egg is produced, so there is nothing for the sperm to fertilize. Pregnancy cannot occur.
"The pill" is used by nearly 16 percent of women aged 15 to 44 years in the United States, and it has both advantages and disadvantages. People with different risk factors may be advised to use a particular kind of pill.
There are different types of contraceptive pills. They all contain synthetic forms of the hormones estrogen, progesterone, or both. Synthetic progesterone is called progestin. Combination pills contain progestin and estrogen. The "mini pill," contains only progestin.
Monophasic pills all contain the same balance of hormones. With phasic pills, two or three different types of pill are taken each month, each with a different balance of hormones.