Progestin-only oral contraceptives are commonly known as “the mini pill”. They differ from combined birth control pills in that they contain only one hormone (progestin) instead of two (estrogen and progestin).
The mini pill prevents pregnancy in several ways. Their main action is to cause thickening of the cervical mucus; this blocks sperm from entering the cervix to reach and fertilize the egg. They can also prevent ovulation, which is the release of eggs from the ovaries as well as cause changes in the lining of the uterus preventing implantation of the pregnancy.
Among perfect users (women who miss no pills and follow instructions perfectly), only about 1 in 200 women (0.20) is expected to become pregnant over one first year of use. Among typical users, about 5 to 7 in 100 women will become pregnant over one year of use. The mini pill is generally less effective than the combined pill.
Women who are unable to take estrogen containing birth control pills or are not interested in injectable progestin-only birth control (Depo-Provera) may be good candidates for the mini pill. This includes if you are over 35 who smoke, if you have a history of high blood pressure, if you are at increased risk forming blood clots, if you experience vascular migraine headaches, and if you are currently exclusively breastfeeding.
You must be very motivated to take the mini pill because if you are more than 3 hours late in taking the mini pill you must use a backup method of birth control (such as condoms) for the next 48 hours
Most women of any age needing birth control can use the mini pill. A woman may not be able to use the mini pill if she has history of:
You must wait for your next period to start the mini pill. This ensures that you are NOT pregnant when you start the mini pill. Start the mini pill on the first day of your next period.
The mini pill may also be started after pregnancy. You may start the mini pill on the same day as a termination of pregnancy. You may also start the mini pill after a fullterm delivery. The mini pill is safe for breastfeeding mothers and can be started six weeks after giving birth. Women who are not breastfeeding can begin the mini pill 3 weeks after delivery.
You must take one mini pill every day. Unlike the combined pill, each mini pill has the same hormone content and there is NOT a hormone free week (week of reminder pills); you must take one mini pill every day. Do NOT skip the last week of pills. It is even more important to take the mini pill at the same time every day as varying the time even by a few hours greatly increases the risk of getting pregnant. The mini pill works by causing the cervical mucus to thicken and create the most effective barrier against sperm and it takes about four hours for this effect to be optimum. Therefore, the best time to take the mini pill is four hours before the most likely time of intercourse. Given that bedtime is the most frequent time of sexual intercourse, taking the mini pill several hours earlier may provide the greatest protection against pregnancy.
If you miss a mini pill:
Missed 1 mini pill. Take the missed mini pill NOW and the next mini pill at the usual time (this may entail taking 2 pills now). If the forgotten pill is more than 3 hours late, use a backup method of birth control (such as condoms) for at least 48 hours. You may have some breakthrough bleeding or spotting for the remainder of the pill pack.
Missed 2 or more mini pills. Take 2 pills NOW and 2 pills a day. There is an increased chance that you could become pregnant. Start using a backup method of contraception immediately. If you have unprotected sex after forgetting your mini pill, ask your doctor about emergency contraception.
Call your doctor if you have any of the following problems: