What is the progesterone-only pill?
The progesterone-only pill (or POP), also known as the mini pill, is a form of contraception taken to prevent pregnancy. The progesterone-only pill contains a synthetic version of the hormone progesterone and - unlike many other forms of hormonal contraception - does not contain any oestrogen.
How does the progesterone-only pill work?
The synthetic progesterone in the POP prevents pregnancy by thickening your cervical mucus. This makes it harder for sperm to enter the womb and fertilise an egg after unprotected sex. Some types of progesterone-only pill also prevent ovulation. Those containing desogestrel (such as Cerazette) prevent ovulation in 97% of cases, alongside thickening cervical mucus.
How do I take the progesterone-only pill?
You should always take the progesterone-only pill as it was prescribed to you by your doctor. The POP must be taken every day without a break (unlike the combined contraceptive pill, which involves a week’s break every month). Most types of the mini pill must also be taken at the same time each day within a window of 3 hours (pills containing desogestrel are an exception to this, allowing for a window of 12 hours).
The combination of these two factors means that you may find it difficult to always remember to take your pill, and on time, which increases the risk of pregnancy. If you are currently taking, or thinking about starting, the progesterone-only pill and are concerned that you might have trouble remembering to take it, you could consider an alternative form of contraception.
Consult our article on different forms of contraception for more information on your options.
What types of progesterone-only pill are there?
Cerazette is one of the most popular brands of progesterone-only pill, as it contains progesterone in the form of desogestrel, meaning there is a 12-hour window in which you can take it and still be protected from pregnancy.
Cerelle is a generic version of Cerazette, as it also contains desogestrel, meaning it also allows for a 12-hour window in which it can be taken. Both Cerazette and Cerelle are available on from our online clinic, with Cerelle being the cheaper option.
Micronor contains progesterone in the form of norethisterone, and must be taken within the same three-hour window each day.
Noriday is a progesterone-only pill containing the same active ingredient as Micronor, norethisterone, and as such must be taken in the same way. Noriday and Micronor are both available from our online clinic.
Norgeston contains progesterone in the form of levonorgestrel, and must be taken within the same three-hour window each day. It is one of the cheapest POPs available. Click here to learn more about Norgeston.
What are the advantages and disadvantages of the progesterone-only pill?
- If taken correctly, the progesterone-only pill can be over 99% effective in preventing pregnancy.
- The mini pill can be taken by women who cannot take oestrogen (this includes women who have high blood pressure, are overweight, have a history of blood clots, and for women over the age of 40)
- If you’re over 35 and smoke, it is still safe for you to take the POP.
- It is safe for most women to take the POP up to the age of 55.
- The mini pill can be taken whilst you are breastfeeding.
- Your periods can become lighter or even stop altogether.
- You must take the progesterone-only pill at the same time every day, usually within a window of 3 hours. This means there can be a higher risk of pregnancy associated with missing the mini pill than with the combined pill.
- You may not be able to take the mini pill if you have had heart disease, liver disease, breast cancer, ovarian cysts or unexplained vaginal bleeding.
- Side effects can include spotty skin and breast tenderness. Some women also develop benign cysts on their ovaries, which do not need treatment but can sometimes cause discomfort.
- Some medications, including certain types of antibiotic, can make the POP less effective.
- Your periods can become irregular or more frequent.
What happens if I forget to take my POP?
If you have forgotten to take your POP on time, but are still within the safe window for that pill (i.e. 3 hours for Micronor, Norgeston and Noriday and 12 hours for Cerazette and Cerelle) then you should take your pill as normal. When taken within the window period, the progesterone-only pill will protect against pregnancy. You will not need to use emergency contraception or barrier methods.
If you have forgotten to take your POP on time, and are not within the safe window for that pill, you will not be protected against pregnancy. You should take your missed pill as soon as you remember (only take one, even if you have missed more than one) and your next pill at the normal time. This may mean that you take two pills on the same day (your missed pill, and your next scheduled pill).
Please be aware that you will not be protected against pregnancy for the next two days, so you should use barrier methods (condoms, or a cap or diaphragm with spermicide) during this period. If you have unprotected sex during this time, you are putting yourself at risk of pregnancy, and may have to seek out emergency contraception.
Which medicines interact negatively with the progesterone-only pill?
Some medicines should not be taken with the progesterone-only pill, so you should always inform your doctor about any other medicines you are taking before seeking a prescription. These include:
- the antibiotics rifampicin and rifabutin
- the epilepsy medicines carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone and topiramate
- St John’s wort
- certain antiretroviral medicines used to treat HIV
What other kinds of contraception are there?
There are many other types of contraception, including:
- the combined contraceptive pill
- the contraceptive implant
- the contraceptive injection
- the IUS (intrauterine system)
- the IUD (intrauterine device)