What is a minipill?

A minipill (or progestin-only pill) is a form of birth control, taken by mouth that contains progestin. Progestin is a synthetic version of the hormone progesterone, which is involved in the menstrual cycle and pregnancy. The minipill is only available by prescription.

Minipills work by:

  • Thickening mucus in the cervix, making it difficult for sperm to travel to the uterus
  • Stopping ovulation, but not consistently
  • Thinning the lining of the uterus to help prevent the fertilized egg from attaching to it

How effective is the minipill?

When starting on the minipill, you are protected against pregnancy right away if you take the pill up to 5 days after the start of your period. If you take your first pill more than 5 days after the start of your period, use additional birth control for the first 2 days.

If you take the minipills on time, they are 99% effective. If some pills are skipped, they are 91% effective. No form of birth control is 100% effective.

How are minipills taken?

Minipills come in packs of 28 pills. As soon as you get the pills you can begin to take them. Or, take the first pill soon after your next period begins.

Take a minipill once a day at the same time each day. When you finish a pack of pills, take a pill from a new pack the next day.

Once you start, don’t go a day without taking the minipill. If you forget to take a pill by more than 3 hours, take a pill as soon as possible. Also, use another method of contraception for the next 2 days. If you become ill within 3 hours of taking the minipill, keep taking the pills. However, use backup contraception until 2 days after you stop being ill.

Follow your doctor’s directions and the prescription label carefully. Ask questions if you do not understand the dosage.

What are the benefits of taking minipills?

The benefits of minipills can include:

  • No interference with intimacy
  • Menstrual bleeding may be reduced or stopped
  • Can be taken even if certain health conditions prevent you from taking other types of birth control
  • Can be used immediately after giving birth if not breastfeeding
  • If breastfeeding, wait 3 weeks after delivery if also giving formula; wait 6 weeks after delivery if only breastfeeding
  • No effect on ability to become pregnant in the future after stopping usage

What complications and side effects are associated with minipills?

You may experience unpredictable bleeding while taking minipills. There could be instances of spotting, heavy bleeding or no bleeding at all. Other side effects might include:

  • Breast tenderness
  • Nausea
  • Headaches
  • Weight change
  • Acne
  • Increased hair growth

Usually these side effects will go away in 2 or 3 months.

What are the precautions and risk factors for taking minipills?

Overall the minipill is safe. However, before taking the minipill:

  • Tell your doctor if you are allergic to any medications, progestins, aspirin, or tartrazine (a yellow food coloring).
  • Tell your doctor if you are taking any vitamins, prescription or nonprescription medications. Your doctor may monitor you closely for side effects or change the dosage.
  • Do not smoke while taking minipills. Smoking can increase risk of heart attacks and stroke.
  • Cancer risks associated with minipills are not consistent when studies are performed. This pill will not prevent the spread of AIDS and other sexually transmitted diseases.

Who should not take minipills?

  • Pregnant women
  • Breast cancer survivors
  • Women with unexplained vaginal bleeding
  • Women with liver tumors
  • Women with jaundice
  • Women with active hepatitis
  • Women with severe cirrhosis

What are other uses for minipills?

Women can take minipills to manage heavy periods.

When should I call my doctor while taking minipills?

You should call your doctor if:

  • You become pregnant while on the minipill
  • You experience severe stomach pain
  • You have late, or a lack of, menstrual periods
  • You have bleeding that lasts a long time
  • You have severe headaches
  • You have an accidental overdose
Care at Cleveland Clinic

Last reviewed by a Cleveland Clinic medical professional on 01/28/2018.


  • U. S. National Library of Medicine. Progestin-Only Oral Contraceptives. (https://medlineplus.gov/druginfo/meds/a602008.html) Accessed 2/12/2018.
  • National Cancer Institute. Oral Contraceptives and Cancer Risk. (https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/oral-contraceptives-fact-sheet) Accessed 2/12/2018.
  • The American Congress of Obstetricians and Gynecologists: Progestin-Only Hormonal Birth Control: Pill and Injection. (https://www.acog.org/Patients/FAQs/Progestin-Only-Hormonal-Birth-Control-Pill-and-Injection) Accessed 5/2/2018.
  • U.S. National Library of Medicine. What are the treatment options for heavy periods? (https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072477/) Accessed 2/14/2018.

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