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Combined oral contraceptive pill

The combined oral contraceptive pill is usually just called ‘the pill’. 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 by stopping egg production. One method of contraception is the combined oral contraceptive pill. 

The hormones in the pill prevent your ovaries from releasing an egg (ovulating). They also make it difficult for sperm to reach an egg or for an egg to implant itself in the lining of the womb.

The pill is usually taken to prevent pregnancy, but can also be used to treat painful and/or heavy periods, premenstrual syndrome (PMS) and endometriosis.

We have included further information about the pill below to help you make an informed choice about your contraception. After reading it, if you think the pill is the right contraception choice for you pop along to one of our clinics and have a chat with one of our specialised nurses or doctors - no appointment is needed.

About the pill

  • when taken correctly, the pill is over 99% effective at preventing pregnancy. This means that fewer than one woman in 100 who use the combined pill as contraception will get pregnant in one year
  • you need to take the pill every day for 21 days, then stop for seven days and during this week you have a period-type bleed. You start taking the pill again after seven days
  • you need to take the pill at the same time every day. You could get pregnant if you don't do this or if you miss a pill or vomit or have severe diarrhoea
  • if you have heavy periods or painful periods the combined pill can help
  • minor side effects include mood swings, breast tenderness and headaches.
  • there is no evidence that the pill makes women gain weight
  • there's a very low risk of serious side effects, such as blood clots and cervical cancer
  • the combined pill is not suitable for women over 35 who smoke or women with certain medical conditions
  • the pill does not protect against sexually transmitted infections (STIs), so using a condom as well will help to protect you against STIs

Starting the pill

Most women can start the pill at any time in their menstrual cycle. There is special guidance if you have just had a baby, abortion or miscarriage. You may need to use additional contraception during your first days on the pill - this depends on when in your menstrual cycle you start taking it.

If you start the combined pill on the first day of your period (day one of your menstrual cycle) you will be protected from pregnancy straight away. You will not need additional contraception.

If you start the 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 seven days.

What to do if you miss a pill

If you miss a pill or pills or you start a pack late this can make the pill less effective at preventing pregnancy. The chance of getting pregnant after missing a pill or pills depends on:

  • when the pills are missed
  • how many pills are missed

A pill is late when you have forgotten to take it at your usual time. You have missed a pill when it is more than 24 hours since the time you should have taken it. Missing one pill anywhere in your pack or starting the new pack one day late isn’t a problem, as you will still be protected against pregnancy (known as having contraceptive cover).

However, missing two or more pills or starting the pack two or more days late (more than 48 hours late) may affect your contraceptive cover. In particular, if you make the seven-day pill-free break longer by forgetting two or more pills, your ovaries might release an egg and there is a risk of getting pregnant. This is because your ovaries are not getting any effect from the pill during the seven-day break.

If you miss a pill follow the advice below. If you are not sure what to do continue to take your pill and use another method of contraception such as condom. Seek advice as soon as possible.

If you have missed one pill, anywhere in the pack:

  • take the last pill you missed now, even if it means taking two pills in one day
  • continue taking the rest of the pack as usual
  • you don’t need to use additional contraception, such as condoms
  • take your seven-day pill-free break as normal

If you have missed two or more pills (you are taking your pill more than 48 hours late) anywhere in the pack:

  • take the last pill you missed now, even if it means taking two pills in one day
  • leave any earlier missed pills
  • continue taking the rest of the pack as usual and use an extra method of contraception for the next seven days
  • you may need emergency contraception
  • you may need to start the next pack of pills without a break (see Starting the next pack after missing two or more pills)

You may need emergency contraception if you have had unprotected sex in the previous seven days and have missed two or more pills (you are taking your pill more than 48 hours late) in the first week of a pack.

You can get advice from any one of our Sexual Health Wirral clinics, your GP or pharmacist. You can also call NHS 111 or the Sexual Health Line on 0300 123 7123.

Vomiting and diarrhoea

If you vomit within two hours of taking the combined 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 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. Speak to your GP or contraception nurse or call NHS 111 for more information, or if your sickness or diarrhoea continues.

Who can use the pill?

If there are no medical reasons why you cannot take the pill and you do not smoke, you can take the pill until your menopause. However, the pill is not suitable for all women. To find out whether the pill is right for you, talk to your GP, practice nurse or pharmacist.

You should not take the pill if you:

  • are pregnant
  • smoke and are 35 or older
  • stopped smoking less than a year ago and are 35 or older
  • are very overweight
  • take certain medicines (ask your GP about this)

You should also not take the pill if you have (or have had):

  • thrombosis (a blood clot)
  • a heart abnormality or heart disease, including high blood pressure
  • severe migraines, especially with aura (warning symptoms)
  • breast cancer
  • disease of the gallbladder or liver
  • diabetes with complications or diabetes for the past 20 years

The pill with other medicines

Some medicines interact with the combined pill and it doesn't work properly. If you want to check your medicines are safe to take with the combined pill, you can:

  • ask your GP, practice nurse or pharmacist
  • read the patient information leaflet that comes with your medicine

Download the Family Planning Association guide to the combined pill.