doctor holding the progesterone only pill

The mini-pill is also called progesterone-only pill, because it only contains one type of hormone. Unlike combined pills, which contain estrogen and progesterone, the mini pill uses progesterone as its only active ingredient. Some people refer to this contraceptive as a progestin only pill. Progestin is the artificial version of the natural hormone progesterone, which is used in many minipills.

Like other contraceptive pills, the mini pill works in three ways. It stops ovulation, prevents sperm from reaching the egg and makes it very difficult for a fertilised egg to implant in the uterus.

Progesterone pills are usually recommended to women who cannot take oestrogen (for example because they are breastfeeding) and are 99% effective against pregnancy when used correctly.

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What is different about the mini-pill?

A package of the mini pill contains 28 active pills - no placebo or 7 days rest like the combined pill – and it's important that you take each pill every day at the same time, no more than three hours late.

If you miss this "time window" (i.e. if you miss a pill), you must take the pill that you forgot as soon as you realise and then keep on taking it as usual on the following days.

However, you will also need to use an additional method of contraception (e.g. a condom) for seven days until the progesterone pill becomes effective again. Some types of pills become effective within two to three days, so you might need to ask your GP about the time frame within which you pill provides protection.

The best solution remains to take it every day and get used to the daily routine, so that you don't forget. Once, you have finished one pack, you can start a new one the following day without interruption – which will help maintain the routine.

Note that if you start taking the mini-pill during the first five days of a period you will enjoy immediate protection against pregnancy. Otherwise you will need to use another method of contraception for two days.

What If I Vomit After Taking A Progesterone Pill?

If you vomit within three hours of taking the mini-pill, you need to keep on taking it every day as usual, as well as using a form of backup contraception (e.g. condoms) for the next seven days.

This advice also applies if you suffer from severe diarrhoea. You should use additional contraception for the time that you are ill and seven days after that.

Mini-pill Effectiveness

When taken correctly, the mini-pill is about as effective as the normal pill in protecting against pregnancy (99% effective).

This means, that one woman in a hundred fall pregnant when using the mini-pill for a year, which is much better than the 85 women in 100 who fall pregnant each year because they don't use any protection at all.

Remember though that progesterone-only pills do not protect against sexually transmitted diseases (STIs).

Are There Different Mini Pill Brands?

There are various mini pill brands on the market. Some progesterone only pill brands, such as Cerazette, Aizea, Cerelle, Zelleta and Nacrez contain a progesterone called desogestrel. Other brands of mini pill, including Micronor und Noriday, use the active ingredient northisterone. There is also one progesterone only pill called Norgeston, which contains levonorgesterel, a hormone which occurs in many combined contraceptives.

Advantages Of Progesterone Only Birth Control

Originally, progesterone-only pills were designed for women who are breastfeeding, since oestrogen tends to affect milk production.

Over time, the mini-pill has also proven a reliable alternative for women who can not take oestrogen because of conditions such as blood clots, high blood pressure or obesity.

It is also suitable for women who are over 35 and smoke, because they are generally advised not to take the combination pill. The progesterone-only pill also helps many women have lighter, less painful periods.

Women who use progesterone pills commonly report irregular bleeding. The progesterone-only pill does not regulate the menstrual cycle in the same way that combination pills do. If irregular bleeding becomes an issue for you, do discuss it with your doctor to check whether your bleeding is a side effect or due to an underlying medical issue.

Disadvantages Of Progesterone Only Birth Control

Much like the combined pill, the mini-pill has to be taken every day. However, many find that using progesterone-only pills is less convenient than combined oral pills.

This is because the mini-pill needs to be taken every day within a three-hour period, while the combined pill can be taken within a twelve-hour period. However, some new progesterone only pills allow for the same 12h time window as combined oral contraceptives.

Possible Mini Pill Side Effects

  • Abdominal pain or cramps
  • Headaches
  • Dizziness
  • Nausea
  • Mood swings
  • Fatigue
  • Acne
  • Breast soreness or discomfort

Side effects of the mini pill are rare and most of these symptoms disappear after the first few months.


Progesterone-only pills may be unsuitable if:

  • You are pregnant
  • You have a cardiovascular disease (i.e. heart or blood circulation issue)
  • You have a liver disease
  • You had or have ovarian cysts
  • You have had breast cancer in the past five years

Additionally, the mini-pill may interact with certain medications (e.g. treatments for epilepsy) so you must make sure you discuss any medical treatment with your doctor.

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