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Minipill (progestin-only birth control pill)By Mayo Clinic staff
Original Article: http://www.mayoclinic.com/health/minipill/MY00991
The minipill, also known as the progestin-only birth control pill, is an oral contraceptive that contains the hormone progestin. Unlike combination birth control pills, the minipill doesn't contain estrogen. The progestin dose in a minipill is lower than the progestin dose in a combination oral contraceptive pill.
The minipill thickens cervical mucus and thins the lining of the uterus (endometrium) — preventing sperm from reaching the egg. The minipill also sometimes suppresses ovulation. For maximum effectiveness, you must take the minipill at the same time every day.
Why it's done
The minipill is a common type of contraception. Your health care provider may recommend the minipill if:
- You're breast-feeding — the estrogen in combination birth control pills is known to interfere with milk supply
- You have certain health problems, such as a high risk of heart disease, blood clots, or a history of high blood pressure or migraines
- You're concerned about the side effects of birth control pills containing estrogen
The minipill is an easily reversible method of contraception. Your fertility may return to normal immediately after you stop taking the minipill.
Your health care provider may also recommend the minipill to help treat sickle cell disease or dermatitis that seems to be related to your menstrual cycle or to reduce iron deficiency anemia.
The minipill isn't appropriate for everyone, however. Your health care provider may discourage use of the minipill if:
- You have breast cancer
- You have unexplained uterine bleeding
- You're taking anticonvulsant or anti-tuberculous agents
An estimated 1 to 13 out of 100 women who use the minipill will get pregnant in the first year of use. The failure rate of the minipill in highly fertile women is higher than that of other hormonal contraceptive methods.
If you become pregnant while taking the minipill, it may be difficult to recognize the signs and symptoms of pregnancy. In addition, if you do conceive there's a slightly higher chance that the pregnancy will be ectopic — when the fertilized egg implants outside the uterus, usually in a fallopian tube.
The minipill won't protect you from sexually transmitted infections, and it may be less effective than combination birth control pills.
Side effects of the minipill may include:
- Breast tenderness
- Decreased libido
- Irregular menstrual bleeding
- Ovarian cysts
- Weight gain
How you prepare
You'll need to request a prescription for the minipill from your health care provider.
As long as you aren't pregnant, you can start taking the minipill at any time — ideally on the first day of your menstrual period. Your health care provider might recommend using a backup method of birth control, such as a male condom, for the first seven days after you start taking the minipill. You might be able to skip the backup birth control if you start taking the minipill:
- During the first five days of your period
- Between six weeks and six months after giving birth if you're fully or nearly fully breast-feeding and haven't had a period
- Within the first 21 days after giving birth if you're not breast-feeding
- The day after you stop using another hormonal method of contraception
- Immediately after an abortion
If you're switching from a combination birth control pill to the minipill, start taking the minipill the day after you take your last active combination birth control pill.
What you can expect
To use the minipill:
- Consult your health care provider about a starting date. Make sure you have a backup method of birth control available if necessary.
- Pick a time to regularly take the pill. It's important to take the minipill at the same time every day. If you take the minipill more than three hours later than usual, avoid sex or use a backup method of birth control for at least two days.
- Be cautious with missed pills. If you miss a minipill, take the missed pill as soon as you remember — even if it means taking two pills in one day. Use a backup method of birth control for at least two days. If you've had unprotected sex, consult your health care provider about emergency contraception.
- Don't take breaks between packs. Always have your next pack ready before you finish your current pack. Unlike combination birth control pills, minipill packs don't contain a week of inactive pills.
If you're taking antibiotics or you experience vomiting or diarrhea while using the minipill, use a backup method of birth control. If your bleeding is particularly heavy or lasts for more than eight days, consult your health care provider.
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