Birth control pills, (also known as “the Pill”), are made of synthetic hormones (estrogen and progesterone) that stop a female from releasing an egg. With no egg, there can be no pregnancy. They also thicken the mucus on the cervix, which makes it difficult for sperm to get through. A birth control pill must be taken every day, at about the same time, in order to work. If a girl misses a pill or takes them at different times on different days, the Pill will be less effective.

The Pill is only available through a prescription. Health care providers will explain when the Pill becomes effective at preventing pregnancy. Generally, pills become effective in one week. Condoms or another birth control method should be used to back up the Pill until it is effective.

When used perfectly—taken every day at around the same time—the Pill prevents pregnancy 99.7 percent of the time. Add in human error—missing a day or taking pills at different times—that rate drops to 92 percent.

Birth control pills sometimes have side effects, both good and bad. They include lighter periods, preventing or lessening menstrual cramps, less acne, a change in appetite, mood swings, bleeding between periods and changes in sex drive. For most people, annoying side effects are gone within three months of beginning the Pill. Birth control pills can increase a girl’s risk of more serious side effects, such as blood clots. However, these are extremely rare among teens. The Pill offers NO protection against sexually transmitted diseases (STDs), so using a condom whenever you have sex is still a good idea.

As we mentioned, a girl will need a prescription from a health care provider to get the Pill. The cost varies, depending on where she goes to get a prescription. Typically, she’ll pay less at a family planning clinic, like Planned Parenthood, versus a drugstore. Health insurance usually covers the Pill but if you don’t want your parents to know that you’re on it, using their insurance will probably tip them off because they will get a statement that lists the services you received from a health care provider. When you call to make the appointment, be sure to ask about confidentiality.

For more information, check out this story.