Progestogen-only pill

What is it?

The progestogen-only pill (POP) contains progestogen and is taken at the same time everyday without a break, which means that pills are also taken during your period. The POP does not contain oestrogen, so is a good option for women who can’t or do not want to take oestrogen (i.e. breast feeding mothers/smokers over 35).1 The POP can be started up to and including the fifth day of your period and protects immediately against pregnancy. If started on any other day, another method of contraception must also be used for 2 days.2 Most POPs have a 3-hour window each day to be effective, however there is one type of POP that has a longer missed pill window of 12 hours.

How does it work?¹

There are different types of POP but they work by:

• Thickening the mucus of the cervix to act as a barrier to sperm
• Stopping the fertilised ovum from settling by keeping the lining of the womb thin
• POPs sometimes stop ovulation

How effective is it?¹

The POP is up to 99% effective when used correctly.

What are the benefits?²

• Does not interrupt sex
• Suitable for breast feeding women
• Can be used if you are a smoker and over 35
• Lighter, less painful periods
• No oestrogen related side effects
• The most recent POP also works mainly by preventing ovulation

What are the drawbacks?²

• You may not have regular periods whilst taking the POP. Your periods may stop altogether or be irregular or more frequent. This may settle down and is not harmful and changing to a different POP may help
• The POP does not protect against STIs, so you may need to use condoms
• You have to remember to take the pill everyday

Are there side effects?¹

• Periods can be irregular
• Can increase the chance of spots, headaches, breast cancer and breast tenderness
• Some women develop cysts on their ovaries - but these are very rarely serious and don’t usually require any treatment
• Can increase the chance of an ectopic pregnancy (baby developing outside of the womb) but still less common than if no contraception is used

You should not take the progestogen-only pill if you are/have had any of the following:²

• You might be pregnant
• Don’t want any changes to your periods
• Have had a heart attack, stroke or breast abnormality
• Have breast cancer or have had breast cancer within the last 5 years
• History of cysts on your ovaries
• Take certain medication that can interfere with the efficacy of the POP
• Have migraines with aura (migraines with bright or flashing lights)

What do I do if I miss a POP?²

You should try to take your POP at the same time every day. If you take your POP within the specified window of your usual time you will still be protected (for most POPs this is 3 hours, however there is one POP which has a 12 hour window). If you exceed any of these missed pill windows you will not be protected against pregnancy and you will need to use additional contraceptive precautions such as condoms for the next 2 days.

What do I do if I want to become pregnant?²

You can try to get pregnancy as soon as you stop taking the POP. You can stop at any time. Ideally you should wait for one period before trying to get pregnant. Waiting means the pregnancy can be dated more accurately and you can start pre-pregnancy care, such as taking folic acid and stopping smoking.

1. NHS direct. Health encyclopedia – progestogen-only pill

2. fpa. Sex/sexual health – contraception – progestogen-only pill