Birth Control Hormones: The Mini-Pill

Topic Overview

What are mini-pills?

Mini-pills are used to prevent pregnancy. They release a regular dose of a hormone called progestin. They are different from regular combination birth control pills. Those contain progestin and another hormone called estrogen.

Progestin prevents pregnancy in a few ways. It thickens the mucus in the cervix. This makes it hard for sperm to travel into the uterus. It also thins the lining of the uterus. This makes it harder for a fertilized egg to attach to the uterus.

And progestin can sometimes stop the ovaries from releasing an egg each month (ovulation).

Mini-pills come in packs. Every pill in the pack contains progestin. There are no spacer pills. You have to take a pill every day at the same time to prevent pregnancy. This means you take a pill even when you have your period.

How well do they work?

In the first year of use:^{footnote 1}

• When mini-pills are taken exactly as directed, fewer than 1 woman out of 100 has an unplanned pregnancy.
• When pills are not taken exactly as directed, such as forgetting to take them sometimes, 9 women out of 100 have an unplanned pregnancy.

Be sure to tell your doctor about any health problems you have or medicines you take. He or she can help you choose the birth control method that is right for you.

What are the advantages of mini-pills?

• Mini-pills work better than barrier methods. Barrier methods include condoms and diaphragms.
• They may cause fewer side effects than combination birth control pills. They may reduce heavy bleeding and cramping.
• They don't contain estrogen. So you can use them if you don't want to take estrogen. They are also an option if you can't take estrogen because you have certain health problems or concerns.
• They are safe to use while breastfeeding.
• You don't have to interrupt sex to use them.

What are the disadvantages of mini-pills?

• Mini-pills don't protect against sexually transmitted infections (STIs), such as herpes or HIV/AIDS. If you aren't sure if your sex partner might have an STI, use a condom to protect against disease.
• They may cause irregular periods. You may have spotting between periods. You may also stop getting a period. Some women see having no period as an advantage.
• Mini-pills may cause mood changes, less interest in sex, or weight gain.
• You must take a pill at the same time every day to prevent pregnancy.