What does the birth control pill do?

There are many different brands of oral contraceptive pills. Most of them are combined, i.e. they include an estrogen and a progestin.

These hormones contained in combined birth control pills intervene in the regulation of the menstrual cycle and prevent unwanted pregnancy through various actions:

• They increase the density of cervical mucus.
• Impede ovulation.
• They alter the endometrium.

However, the contraceptive pill is not a barrier method of contraception and does not protect against sexually transmitted diseases (STDs).