The Progestin-Only Birth Control Pill

Also Known as 'The MiniPill' or POPs

The progestin-only birth control pill, traditionally known as the minipill, is a type of oral contraceptive (birth control pill). Each progestin-only pill contains a small amount of progestin (which is a synthetic form of the hormone progesterone). These pills do not have any estrogen.

An assortment of different types of birth control pills
Photo © 2014 Dawn Stacey


The traditional progestin-only birth control pills mainly prevent pregnancy by changing the consistency of your cervical mucus. The progestin thickens your mucus, and this makes it much harder for sperm to get through.

The minipill may also work by thinning the lining of your uterus. This would make it less likely for implantation to happen. Traditional progestin-only pills may also stop you from ovulating (this is the case for about half of the women who use them).


Because the minipill contains less progestin than the combination pill, the progestin's effect on your cervical mucus lasts for only about 24 hours. That is why the traditional minipill must be taken at the same time every day.

If you miss a dose of the mini pill by more than 3 hours, you need to use a backup contraception (such as condoms) or avoid sexual intercourse until pills have been taken correctly, on time, for 2 consecutive days.

That being said, the progestin-only birth control pill is a very effective contraceptive. The minipill is 91% to 99% effective. This means that with typical use, 9 out of every 100 women will become pregnant during the first year of use.

Before Taking

Because minipills do not contain estrogen, they can be a good alternative for women who cannot use combination hormonal contraceptives.

Contraindications to estrogen use include:

  • Cigarette smokers over the age of 35.
  • Women with a history of blood clots.
  • Women with high blood pressure.
  • Women who experience extreme migraine headaches or migraine with aura.

The Minipill and Breastfeeding

Progestin-only birth control pills can be prescribed for breastfeeding mothers since the progestin will not negatively affect milk production or harm a breastfeeding baby.

Precautions and Contraindications

Women who should not take the minipill include those with:

  • Active liver disease
  • Undiagnosed vaginal bleeding
  • Breast cancer, known or suspected
  • Pregnancy, known or suspected


Traditionally the minipill was only available in a 28-day pack. All 28 pills contain progestin (there are no placebo pills). You take one pill every day for the four-week cycle (pack). This way, you are getting a steady dose of the hormone.

The newest formulation of the progesterone-only pill (drospirenone 4 mg) has 24 active pills and 4 pills without any hormone. You should take each pill at the same time each day; if you miss a pill you have more time to make it up compared to the traditional mini pill. This newest formulation works primarily by suppressing ovulation

You will likely have your period while you are still taking "active" pills. If you typically have a 28-day cycle and start your progestin-only pill on the first day of your menstrual cycle, you will most likely get your period during the first week of your next pack.

Only about 50% of women who use the minipill will ovulate regularly, which makes it difficult to predict when your period may occur. Progestin-only birth control pills do not regulate your cycle the same way that combination pills do.

Progestin-Only vs. Combination Pills

Even though both of these pill types are considered to be hormonal contraception, there are some differences between the two to be aware of.

Progestin-Only Pill
  • Contains less progestin than combination pill

  • Slightly less effective

  • Fewer side effects

  • Must be taken at same time every day

Combination Pill
  • Contains more progestin than progestin-only pill

  • Slightly more effective

  • More side effects

  • Some flexibility in time of day taken

Progestin Amount

The amount of progestin in traditional progestin-only pills (the minipill) is 0.35 milligrams (mg) norethindrone. The new formulation has 4 mg of drospirenone. The typical combination pill contains norethindrone 0.4 mg or higher and drospirenone 3 mg. The amount of progestin in progestin-only pills is lower than the progestin dose in combination birth control pills. The new formulation has slightly more progestin but no estrogen


Progestin-only birth control pills are slightly less effective than the combined pill.

Side Effects

Unscheduled bleeding is the most common side effect in the progestin-only pill and the biggest cause of discontinuation. Other side effects can include acne, mood changes, and weight gain.

Ease of Use

Some women say that traditional progestin-only birth control pills are harder to use than combination pills. This is because the minipill must be taken at the same time each day. Because combination birth control pills are made up of progestin and estrogen, you have a little more flexibility if you don't take your pill at exactly the same time.

Frequently Asked Questions

  • Do you still get a period on the mini pill?

    Yes, you will still get your period when taking progestin-only birth control. Some women also experience breakthrough bleeding or spotting throughout the month.

  • Is the mini pill less effective than regular birth control pills?

    Yes, but only slightly. Progestin-only birth control pills do not always prevent ovulation as combination pills do. As a result, they have slightly higher rates of failure with typical use.

  • Does the mini pill cause weight gain?

    Possibly. Weight gain is a common complaint of women taking hormonal birth control. However, research suggests the mini pill has a minimal effect on weight. A Cochrane review of 22 studies found women on progestin-only birth control gained an average of 4 pounds over 12 months.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Reproductive health. Progestin-only pills.

  2. Edlow AG, Bartz D. Hormonal contraceptive options for women with headache: a review of the evidence. Rev Obstet Gynecol. 2010;3(2):55-65.

  3. The American College of Obstetrians and Gynecologists. Progestin-only hormonal birth control: Pill and injection.

  4. Lopez LM, Ramesh S, Chen M, et al. Progestin-only contraceptives: effects on weight. Cochrane Database Syst Rev. 2016;2016(8):CD008815. doi:10.1002/14651858.CD008815.pub4

By Dawn Stacey, PhD, LMHC
Dawn Stacey, PhD, LMHC, is a published author, college professor, and mental health consultant with over 15 years of counseling experience.