If you start your pill in the first five days of your cycle then it will be effective immediately. If you start your pill at any other time on your cycle then you should use additional protection for 48 hours.

The progestogen only pill may prevent ovulation and therefore prevent you going through your usual menstrual cycle.

There are two types of POP:

	3 hour Progestogen-only pill must be taken within three hours of the same time every day. Common brands include: Femulen, Micronor, Norgeston and Noriday
	12 hour Progestogen-only pill must be taken within 12 hours of the same time every day. Common brands include: Cerazette.

The chance of getting pregnant depends on when the pills are missed, how many pills are missed and whether you have had sex with out using another form of contraception such as condoms.

First check your pill packet.

If you are on a pill containing desogestrel then you are taking a 12 hour pill. This means that each pill must be taken within 12 hours of the same time every day.

If you are less than 12 hours late, then take the missed pill as soon as you remember and take your next one on time. You do not need to take extra precautions as the pill will still work, and you’ll be protected against pregnancy.

If you are more than 12 hours late, then take your missed pill as soon as you remember it, take the next one on time and keep taking the pill. You may want to consider emergency contraception. You will not be protected until you have taken two more pills at the correct time and will need to use condoms when you have sex for those two days. You will be able to rely on your pill for contraception again at about the time that you are due to take your third pill.

If you are on a pill containing norethisterone or levonorgestrel, then you are taking a three hour pill. This means that the pill must be taken within three hours of the same time every day.

If you are less than three hours late, then take the missed pill as soon as you remember and take your next one on time. You do not need to take extra precautions as the pill will still work, and you’ll be protected against pregnancy.

If you are more than three hours late, then take your missed pill as soon as you remember it, take the next one on time and keep taking the pill. You may want to consider emergency contraception. You will not be protected until you have taken two more pills at the correct time and will need to use condoms when you have sex for those two days. You will be able to rely on your pill for contraception again at about the time that you are due to take your third pill.

If you vomit within two hours of taking the 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 (7 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 (6 to 8 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 (7 days if you are taking a 12-hour pill).

Speak to your GP or contraception nurse or call NHS 111 for more information, or if your sickness or diarrhoea continues.

You may not be able to take POP if you have or have had:

• heart disease or a stroke
• disease of the liver
• systemic lupus erythematosus
• breast cancer.

Speak to your GP or sexual health clinic about whether POP is right for you.

If you are healthy and there are no medical reasons for you not to take the POP, you can take it until your menopause or until you are 55 years old.

Some reports suggest that there may be a very small increased risk of breast cancer and ovarian cancer, but the pill does help protect against other types of cancers such as womb, colon and uterine cancers.

There is no evidence to suggest the pill causes infertility. Most women who have regular periods will find that their normal cycle will return within six months. Some women find that their usual cycles begin again very quickly after stopping, but for others it can take longer.

Some reports suggest that there may be a very small increased risk of breast cancer and cervical cancer, but the pill does help protect against other types of cancers such as ovarian, colon and uterine cancers.

Some women may develop small fluid-filled cysts on their ovaries. These are not dangerous and do not usually need to be removed.

When you first start the pill you will usually be given three months' supply to see how it suits you. After that you should go back to the doctor or nurse to get new supplies and to have your blood pressure checked. If there are no problems, you can be given up to a year’s supply of the pill.

You may sometimes be provided with or prescribed a different brand of pills, but the nurse or clinician will explain that the hormones and doses will be the same. The clinics are likely to stock the pill that was cheaper at the time.

The POP has a different hormone than the combination in the combined pill, so if you have had side effects on the combined pill then you may wish to try the progestogen only pill as an alternative.

Yes, you can easily change between pills.

Some women find that their weight changes due to fluid retention or an increase in appetite, but this should settle over time.

Some medicines make the progestogen only pill less effective (including those used to treat epilepsy, HIV and TB, and the herbal medicine St John’s Wort). Ask your GP, clinician or pharmacist and read the information that comes with your medicine.

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.

Always tell your doctor that you are taking the progestogen only pill if you are prescribed any medicines.

When you stop using the POP your fertility will return to normal. (Don’t worry if your periods don’t start immediately. For some women it can take a few months).

Yes, you can use the POP after having a baby.

Yes, you can use the POP while breastfeeding.