The minipill: progestin-only birth control

While many types of birth control contain a combination of the hormones estrogen and progestin, what's called the minipill is progestin-only. 

You might consider taking the minipill if you need to avoid estrogen, are breastfeeding, or want to sidestep any side effects or risks associated with combination hormonal birth control. 

The minipill needs to be taken at the same time every day for it to work like it’s supposed to. If you take it more than three hours late, you should use a backup method of birth control. 

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Much like other birth control pills, the minipill prevents pregnancy mostly by changing cervical mucus at the entrance to the uterus, making it harder for the sperm to reach an egg. It can also block ovulation during some menstrual cycles. There are lots of brand names of minipill on the market. 

Because the minipill doesn’t contain estrogen, it’s a good option for people who can’t take estrogen. This could be because they’re breastfeeding, have high blood pressure, experience heart problems, or for those who simply don’t want to. 

While combined oral contraceptives are very effective, they’re not without side effects and risks. Using combination birth control pills with estrogen and progestin increases the risk of developing a blood clot or stroke, especially if you have a history of blood clots or if you smoke cigarettes (de Bastos, 2014; Roach, 2015). 

But combination birth control pills have their benefits, too. While progestin-only pills must be taken at exactly the same time every day to prevent pregnancy, there’s a little bit more flexibility when it comes to taking combined oral contraceptives. Birth control that contains estrogen can also prevent breakthrough bleeding (bleeding between periods), give you lighter periods (or no periods) if taken continuously. You may also experience less severe menstrual cramps while taking them.

You have lots of options when it comes to birth control and you can decide which one makes the most sense for you. Some people may choose the minipill to avoid the risks of combined oral contraceptives. Researchers have found no evidence that the minipill leads to weight gain, depression, or blood clots (Lopez, 2016; Worly, 2018; Tepper 2016). You can also take it when breastfeeding, whereas estrogen-containing pills can affect your milk supply and shouldn’t be taken when nursing.

When taken as directed, the minipill is just as effective as combined oral contraceptives at preventing pregnancy (Graham, 1982). With typical use, however, about 9 out of 100 people become pregnant in the first year of use with progestin-only pills. 

The minipill doesn’t stop your ovaries from releasing eggs in every cycle. It stops ovulation about half the time, but that varies widely across individuals. Because minipills mainly work by changing the consistency of your cervical mucus, fluctuations in the levels of the hormone in your system can change how effective they are. 

For most types of minipill, you need to take it at the exact same time each day. If you miss your daily dose by three hours or more, you’ll need to use a backup form of birth control, like a condom, to prevent pregnancy.

Depending on when you start taking the minipill for birth control, you may need to use a backup method for a few days. If you start taking it within five days of when your period started, you don’t need to use backup contraception. If you start taking it more than five days after your bleeding started, you should use a backup for the next two days. 

Typically, you don’t need any tests or exams before being prescribed the minipill, but tell your healthcare provider about any underlying medical conditions you have or any medications or supplements you are taking.

If you’ve ever heard of Plan B, you might not know that it’s actually made up of progesterone-only birth control just like the minipill. Plan B can be taken up to 72 hours after unprotected sex to prevent pregnancy, but the sooner you take it after sex the more effective it is. Also known as the "morning after pill,” it’s available under several different brand names (Plan B One Step, Take Action, My Way) and can be purchased over-the-counter at most drug stores and pharmacies.  

If you take the morning-after pill, you may have some side effects from it, like irregular bleeding, headaches, acne, nausea, or vomiting.

If you’re looking for a progestin-only birth control option, the minipill isn’t your only choice. If taking a pill every day isn’t for you, there are plenty of other options. The birth control shot, implant, and an intrauterine device (IUD) all come in progestin-only forms. And none of them will affect your ability to get pregnant once you stop using them. The implant and IUD have to be removed by a healthcare professional, though, whereas you can stop taking the pill whenever you like.

Injection (shot)

The shot (depot-medroxyprogesterone acetate or DMPA), known by the brand name Depo-Provera, is an injection administered by a healthcare provider once every three months. It carries a warning about bone mineral density loss, which increases the longer you use Depo-Provera, so this option shouldn’t be used for more than two years. If you do use it long-term, your healthcare provider should monitor your bone mineral density (FDA, 2010).

About six out of 100 people who use this method become pregnant in the first year of use (CDC, 2016). Side effects can include a change in bleeding patterns and abdominal discomfort. 

Implant

The birth control implant contains only progestin and is available as the brand name Nexplanon. A healthcare provider inserts it under the skin in your upper arm and it can stay there for up to three years. It’s more than 99% effective at preventing pregnancy. 

Like many other forms of birth control, the most common side effect is a change in menstrual bleeding patterns. The implant is an easy-to-use option but it’s not for everyone. People who have a history of blood clots, or certain liver conditions shouldn’t use it.

Intrauterine device (IUD) 

Intrauterine devices (IUDs) are small, T-shaped devices that can be inserted into the uterus by a healthcare provider. 

Some release small amounts of the hormone progestin while others are hormone-free. Progestin-only IUDs are available under the brand name Mirena. Unlike birth control pills that you need to take daily, IUDs can be left in place for up to six years. 

In addition to being used to prevent pregnancy, they’ve also been shown to be effective at alleviating heavy menstrual bleeding. IUDs that contain hormones can actually stop your period altogether. 

There are many choices for birth control out there. A progestin-only method of contraception like the minipill is worth thinking about if you want to avoid the risks of combination birth control with estrogen or if you’re breastfeeding. 

Be sure to talk openly with your healthcare provider about your options and ask questions along the way. Make sure you know how to take the minipill so it works best––that might mean taking it at the same time every day, or knowing when to use a backup method if you don’t.

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Current version

July 07, 2021

Written by

Danielle Oaks

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.