A woman can get pregnant if a man’s sperm reaches one of her eggs (ova). Contraception tries to stop this happening by keeping the egg and sperm apart or stopping egg production. One method of contraception is the progestogen-only pill (POP).
What is the progestogen-only pill?
It contains the hormone progestogen, but doesn’t contain oestrogen.
You need to take the progestogen-only pill at or around the same time every day.
The progestogen-only pill thickens the mucus in the cervix, which stops sperm reaching an egg. In can also stop ovulation, depending on the type of progestogen-only pill you take.
Newer progestogen-only pills contain desogestrel.
- If taken correctly, it can be more than 99% effective. This means that fewer than 1 woman in 100 who uses the progestogen-only pill as contraception will get pregnant in one year.
- You take a pill every day, with no break between packs of pills.
- The progestogen-only pill can be used by women who can’t use contraception that contains oestrogen.
- You can take the progestogen-only pill if you’re over 35 and you smoke.
- You must take the progestogen-only pill at the same time each day. If you take it more than three hours late – or 12 hours late if you take a desogestrel pill, such as Cerazette – it may not be effective.
- If you’re sick (vomit) or have severe diarrhoea, the progestogen-only pill may not work.
- Some medicines may affect the progestogen-only pill’s effectiveness – ask your doctor for details.
- Your periods may stop or become lighter, irregular or more frequent.
- Side effects may include spotty skin and breast tenderness – these should clear up within a few months.
- The progestogen-only pill doesn’t protect against sexually transmitted infections (STIs). By using condoms as well as the progestogen-only pill, you’ll help protect yourself against STIs
How it prevents pregnancy
The progestogen-only pill works by thickening the mucus in the neck of the womb, so it’s harder for sperm to penetrate into the womb and reach an egg.
Sometimes, depending on the type of progestogen-only pill, it may also prevent ovulation, where an egg is released from your ovaries each month.
The desogestrel pill (a 12-hour pill, such as Cerazette) stops ovulation in 97% of menstrual cycles. This means that if you’re using a 12-hour progestogen-only pill, you won’t release an egg in 97 cycles out of 100.
Using the progestogen-only pill
There are two different types of progestogen-only pill:
- three-hour progestogen-only pill – must be taken within three hours of the same time each day; examples are Micronor, Norgeston and Noriday
- 12-hour progestogen-only pill (desogestrel pill, such as Cerazette) – must be taken within 12 hours of the same time each day
It’s important to follow the instructions that come with your pill packet. Missing pills or taking the pill alongside other medicines can reduce its effectiveness.
There are 28 pills in a pack of progestogen-only pills. You need to take one pill every day within either three or 12 hours of the same time each day, depending on which type you are taking.
There’s no break between packs of pills – when you finish one pack, you start the next one the next day.
Starting the first pack of pills
- Choose a convenient time in the day to take your first pill.
- Continue to take a pill at the same time each day until the pack is finished.
- Start your next pack of pills the following day. There is no break between packs of pills.
You can start the progestogen-only pill at any time in your menstrual cycle.
If you start it on day one of your menstrual cycle (the first day of your period), it will work straight away and you will be protected against pregnancy. You won’t need additional contraception.
If you start the progestogen-only pill on day five of your menstrual cycle or earlier (the fifth day after the start of your period or before), you will be protected from pregnancy straight away unless you have a short menstrual cycle (your period is every 23 days or less).
If you have a short menstrual cycle, you will need additional contraception, such as condoms, until you have taken the pill for two days.
If you start the progestogen-only pill on any other day of your cycle, you will not be protected from pregnancy straight away and will need additional contraception until you have taken the pill for two days.
After having a baby
If you have just had a baby, you can start the progestogen-only pill on day 21 after the birth. You will be protected against pregnancy straight away.
If you start the progestogen-only pill more than 21 days after giving birth, you will need additional contraception such as condoms until you have taken the pill for two days.
After a miscarriage or abortion
If you have had a miscarriage or abortion, you can start the progestogen-only pill up to five days afterwards and will be protected from pregnancy straight away.
If you start the pill more than five days after a miscarriage or abortion, use additional contraception until you have taken the pill for two days.
What to do if you miss a pill
If you forget to take a progestogen-only pill, what you should do depends on:
- the type of pill you are taking
- how long ago you missed the pill and how many pills you have forgotten to take
- whether you have had sex without using another form of contraception in the previous seven days
If you are less than three or less than 12 hours late taking the pill
If you are taking a three-hour progestogen-only pill and are less than three hours late taking it, or if you are taking the 12-hour progestogen-only pill and are less than 12 hours late:
- take the late pill as soon as you remember, and
- take the remaining pills as normal, even if that means taking two pills on the same day
The pill will still work, and you’ll be protected against pregnancy – you do not need to use additional contraception.
Don’t worry if you have had sex without using another form of contraception. You do not need emergency contraception.
If you are more than three or more than 12 hours late taking the pill
If you are taking a three-hour progestogen-only pill and are more than three hours late taking it, or are taking the 12-hour progestogen-only pill and are more than 12 hours late, you will not be protected against pregnancy.
What you should do:
- take a pill as soon as you remember – only take one, even if you’ve missed more than one pill
- take the next pill at the usual time – this may mean taking two pills on the same day (one when you remember and one at the usual time); this is not harmful
- carry on taking your remaining pills each day at the usual time
- use extra contraception such as condoms for the next two days (48 hours) after you remember to take your missed pill, or don’t have sex
- if you have unprotected sex during the two days after you miss your pill, you may need emergency contraception – get advice from your contraception clinic or GP
It takes two days for the progestogen-only pill to thicken cervical mucus so sperm cannot get through or survive. The Faculty of Sexual Health and Reproductive Healthcare advises using extra contraception for two days after you remember to take your pill.
The patient information leaflet that comes with your pill might say to use condoms for the next seven days after you remember to take your pill. This is because it takes seven days for the pill to suppress ovulation.
Vomiting and diarrhoea
If you vomit within two hours of taking a progestogen-only pill, it may not have been fully absorbed into your bloodstream. Take another pill straight away and the next pill at your usual time.
If you don’t take the replacement within three hours (or 12 hours for the 12-hour pill) of your normal time, use additional contraception, such as condoms, for two days (seven days for the 12-hour pill).
If you continue to be sick, keep using another form of contraception while you’re ill and for two days after recovering.
Very severe diarrhoea – six to eight watery stools in 24 hours – may also mean that the pill doesn’t work properly.
Keep taking your pill as normal, but use additional contraception, such as condoms, while you have diarrhoea and for two days after recovering, or seven days if you’re taking a 12-hour pill.
Speak to your GP or contraception nurse or call NHS 111 or the Sexual Health Line on 0300 123 7123 if you’re unsure whether you’re protected against pregnancy, or if your sickness or diarrhoea continues.
Who can use the progestogen-only pill?
Most women can use the progestogen-only pill.
You may not be able to use it if you’ve had:
- heart disease
- liver disease
- breast cancer
- cysts on your ovaries
- unexplained vaginal bleeding
If you’re healthy and there are no medical reasons why you should not take the progestogen-only pill, you can take it until your menopause or until you are 55.
Breastfeeding
The progestogen-only pill is safe to use if you are breastfeeding. Small amounts of progestogen may pass into your breast milk, but this is not harmful to your baby. The progestogen-only pill does not affect the way your breast milk is produced.
Pregnancy
Although it’s very unlikely, there is a very small chance that you could become pregnant while taking the progestogen-only pill.
If this happens, there is no evidence that the pill will harm your unborn baby. If you think you may be pregnant, speak to your GP or visit your local contraception clinic.
Get medical advice if you have a sudden or unusual pain in your tummy (abdomen), or if your period is much shorter or lighter than usual. It’s possible that these are warning signs of an ectopic pregnancy, although this is rare.
Advantages and disadvantages
Some advantages of the progestogen-only pill include:
- it does not interrupt sex
- you can use it when breastfeeding
- it’s useful if you cannot take the hormone oestrogen, which is in the combined pill
- you can use it at any age – even if you smoke and are over 35
- it can reduce the symptoms of premenstrual syndrome (PMS) and painful periods
Some disadvantages of the progestogen-only pill include:
- you may not have regular periods while taking it – your periods may be lighter, more frequent, or may stop altogether, and you may get spotting between periods
- it does not protect you against STIs
- you need to remember to take it at or around the same time every day
- some medications, including certain types of antibiotic, can make it less effective
Side effects
The progestogen-only pill is generally well tolerated and side effects are rare. Some side effects can include:
- acne
- breast tenderness and breast enlargement
- an increased or decreased sex drive
- mood changes
- headache and migraine
- nausea or vomiting
- small fluid-filled sacs called cysts on your ovaries – these are usually harmless and disappear without treatment
- stomach upset
- weight gain
These side effects are most likely to occur during the first few months of taking the progestogen-only pill, but they generally improve over time and should stop within a few months.
If you have any concerns about your contraceptive pill, see your GP or practice nurse. They may advise you to change to another pill or a different form of contraception.
The progestogen-only pill with other medicines
When you take two or more medicines at the same time, the effects of one medicine can be changed by the other. This is known as an interaction.
Some medicines interact with the progestogen-only pill and it doesn’t work properly. Some interactions are listed on this page, but it is not a complete list.
If you want to check whether your medicines are safe to take with the progestogen-only pill, you can:
- ask your GP, practice nurse or pharmacist
- read the patient information leaflet that comes with your medicine
Antibiotics
The antibiotics rifampicin and rifabutin, which can be used to treat illnesses including tuberculosis and meningitis, can reduce the effectiveness of the progestogen-only pill. Other antibiotics do not have this effect.
If you are prescribed rifampicin or rifabutin, you may need additional contraception such as condoms while taking the antibiotic and for 28 days after. Speak to your doctor or nurse for advice.
Epilepsy and HIV medicines, and St John’s wort
The progestogen-only pill can interact with medicines called enzyme inducers. These speed up the breakdown of progestogen by your liver, reducing the effectiveness of the progestogen-only pill.
Examples of enzyme inducers are:
- the epilepsy drugs carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone and topiramate
- St John’s wort, a herbal remedy
- some antiretroviral medicines used to treat HIV – research suggests interactions between these medicines and the progestogen-only pill can affect the safety and effectiveness of both
Your GP or nurse may advise you to use an alternative or additional form of contraception while taking any of these medicines.
Risks of taking the progestogen-only pill
The progestogen-only pill is very safe to take. However, as with the combined contraceptive pill, there are certain risks. These risks are small. For most women, benefits of the progestogen-only pill outweigh the risks.
Ovarian cysts
Some women can develop fluid-filled cysts on their ovaries. These are not dangerous and don’t usually need to be removed.
The cysts usually disappear without treatment. In many cases, the cysts do not cause symptoms, although some women experience pelvic pain.
Breast cancer
Research is continuing into the link between breast cancer and the progestogen-only pill.
Research suggests women who use any type of hormonal contraception have a slightly higher chance of being diagnosed with breast cancer compared with people who don’t use hormonal contraception.
However, 10 years after you stop taking the pill, your risk of breast cancer goes back to normal.
If you have a family history of breast cancer, you may feel that this increase in risk, however small it is, is not worth taking.
However, doctors do not think using the contraceptive pill is likely to increase the risk in women who already have close relatives with breast cancer.
Where you can get the progestogen-only pill
Most types of contraception are available for free in the UK. Contraception is free to everyone through the NHS. Places where you can get contraception include:
- some GP surgeries – talk to your GP or practice nurse
- contraception clinics
- some young people’s services - call 0300 123 7123 for more information
If you’re under 16 years old
If you’re under 16 and want contraception, the doctor, nurse or pharmacist won’t tell your parents (or carer) as long as they believe you fully understand the information you’re given, and your decisions.
Doctors and nurses work under strict guidelines when dealing with people under 16. They’ll encourage you to consider telling your parents, but they won’t make you.
The only time a professional might want to tell someone else is if they believe you’re at risk of harm, such as abuse. The risk would need to be serious, and they would usually discuss this with you first.