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Birth Control Pills — Progestin-Only Contraceptives

What are progestin-only birth control pills?

Progestin-only birth control pills, often called “mini pills,” are used to prevent pregnancy. “Regular” birth control pills contain two hormones: estrogen (ESS-tre-jen) and progestin (pro-JESS-ten). Mini pills contain progestin only. These hormones are like those made by your body.

Who should use mini pills?

  • Women who should use mini pills include:
    • Women who have had side effects from birth control pills that have estrogen in them. This includes women who have a history of blood clots or breast cancer. 
    • Women who have had side effects from birth control pills that have estrogen in them (even in very low doses).
    • Breastfeeding or postpartum mothers. They can use mini pills according to the manufacturer’s guidelines. The pill will not affect the quality or amount of breast milk or the health of the nursing baby.
    • Any other women who would prefer a pill without estrogen and can remember to take her pill at the same time every day.

How effective are mini pills?

With typical use, about 8 out of 100 women who take the pill may become pregnant within 1 year. This means it is 92 percent effective in preventing pregnancy. If you take the pill exactly as directed (correct and consistent use), less than 1 out of 100 women may become pregnant in 1 year.

How does the mini pill work?

The mini pill thickens the mucus produced by the cervix at the top of the vagina. Because the mucus is thicker, sperm cannot swim through it. They cannot get into the uterus or fallopian tube to fertilize an egg.

How do I start the mini pill?

Your doctor or nurse will suggest 1 of the following methods to begin taking the mini pill:

  • Start the first pill pack on the first day of your menstrual period. Use another method of birth control (such as condoms with spermicide) each time you have sex until you start the pills. The pill will start working right away for birth control if you start on the first day of your period.
  • Start the pills on the first Sunday after your menstrual period begins, whether or not you are still bleeding. You will need to use a backup method of birth control (condoms with spermicide) during the first 7 days of the pill package.
  • Start the pills today. Use a backup method of birth control (such as condoms with spermicide) during the first 7 days of the pill pack?

How do I take the min pill correctly?

  • Take 1 pill at the exact same time each day
  • Never miss a day of taking your pills. If you miss taking your pill by more than 3 hours, the mini pill will no longer keep the mucus thick. When the mucus becomes thinner, sperm can move through it more easily. Taking the pill at the same time every day is extremely important.
  • Every pill in the pack contains the hormone progestin. There are no placebo pills (also called “period” pills or “reminder pills”) in the pack.
  • Start a new pill pack the day after taking the last pill from the old pack. Call your doctor or nurse to schedule a birth control pill refill appointment when you have 2 packs of pills left. Plan ahead so you don’t run out of pills before your appointment.

What should I do if I miss a pill?

Be careful not to miss a pill, but if you do?

  • Take the pill as soon as you remember that you missed it.
  • Take the next pill at the correct time.
  • If you miss taking your pill by more than 3 hours, cervical mucus will become thin. This means the pill will not protect as well against pregnancy. Use a backup birth control method (such as condoms with spermicide) with your pills for the next 48 hours.

If you have sex when you have not been taking your pill correctly, or if the back-up method fails (for example, the condom breaks), you should use emergency contraception to prevent pregnancy. If you do not already have emergency contraception at home, you can visit a drug store to buy ECP (emergency contraception pills, sometimes called the morning-after pill).

One brand of ECP (such as Plan B One-Step® or Next Choice®), is often kept behind the pharmacy counter so you have to ask for it but you do not need a prescription unless you are under the age of 17. Another brand of ECP, called ella®, requires a doctor’s prescription for women of all ages.

You may see some vaginal bleeding or spotting after you miss taking pills. This is normal. Do not stop taking your pills if this happens. Take them as directed.

If you have any questions, call your doctor or nurse.

What are the side effects of the mini pill?

When mini pills are first started, some women will have minor side effects. These usually go away within the first 3 months of pill use.

Side effects can include:

  • bleeding or spotting between expected menstrual periods
  • irregular menstrual bleeding
  • breast tenderness
  • mood changes, depression

If these happen, do not stop taking your pills. If you become very concerned about your symptoms, call or visit your doctor.

Because mini-pills do not contain estrogen, they have not been associated with an increased risk of blood clots. However, call your doctor right away if you have:

  • severe belly pain
  • bad chest pain, shortness of breath, coughing up blood
  • headaches that do not go away
  • changes in vision, such as blurred vision, flashing lights or blindness
  • loss of feeling in any body part
  • calf or thigh pain which makes it hard to walk

Will other medicines affect the way mini pills work?

Some drugs can prevent the mini pill from working well. Talk with your doctor if you take any of these drugs.

These include:

  • Drugs to prevent seizures (anticonvulsant drugs): phenobarbital, carbamazepine (Tegretol®), primidone, ethosuximide, and phenytoin (Dilantin®), barbiturates, topiramate, and oxcarbazepin
  • Antibiotics: Rifampin (rifampicin), griseofulvin. If you are taking these antibiotics, it is recommended that you use a back-up method (condoms or spermicide). Continue to take your mini pills and use a backup method of birth control (condoms with spermicide) during the time you take the antibiotics. Continue to use the backup method for 48 hours after the prescription is finished.
  • Anti-HIV medications
  • St. John’s Wort: Some recent studies suggest that St. John’s Wort may affect how well birth control pills work. If you think you must use St. John’s Wort, talk with your doctor.


If you have any questions or need more information, call your doctor.

Use condoms the right way

To protect against STDs (sexually transmitted diseases), use condoms the right way.

Except for not having sex (abstinence), latex condoms give the best protection from many STDs including HIV, the virus that causes AIDS. Condoms are helpful only if used the right way. Use a latex condom every time you have sex. Always put the condom on before the penis touches or enters the vagina. If you or your partner has an allergy to latex, you should use a plastic (polyurethane) condom.

Important steps for using condoms the right way:

  1. Check the expiration date.
  2. Check the condition of the package.
  3. Open the package carefully.
  4. Hold the condom by the last 1/2 inch at the tip, and squeeze out the air.
  5. If the penis is uncircumcised, pull back the foreskin.
  6. Place the condom on the tip of the penis.
  7. Unroll the condom to the base of the penis. Smooth out any extra air.
  8. If you want or need to use lubricant on the condom, only use water-based lubricants like K-Y Jelly or Surgilube. Do not use oil-based lubricants. They can weaken condoms and cause them to break. Do not use petroleum jelly, cooking or vegetable oil, mineral or baby oil, massage oil, butter, margarine, oil-based creams, or lotions.
  9. Immediately after ejaculation, hold the condom firmly by the rim at the base of the penis, and pull the penis and condom out of the vagina together, while the penis is still erect.
  10. Look carefully at the condom to see if there is a hole in it. If you are not sure, fill the condom with water to see if it leaks.
  11. Discard the condom. Wrap it in tissue, and throw it away. Do not flush it down the toilet.
  12. Never re-use a condom.

For UPMC Mercy patients: UPMC Mercy, a Catholic hospital, abides by the Ethical and Religious Directives for Catholic Health Care Services, as determined by the United States Conference of Catholic Bishops. As such, UPMC Mercy neither endorses nor provides medical practices or procedures that contradict the moral teachings of the Roman Catholic Church.​​

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