Combined contraceptive pill
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The combined oral contraceptive pill is usually just called the pill. It contains synthetic (artificial) versions of the female hormones oestrogen and progesterone, which women produce naturally in their ovaries.
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 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 periods, heavy periods, premenstrual syndrome and endometriosis.
The pill is usually taken to prevent pregnancy, but it can also be used to treat:
How effective is it?
- 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.
How the pill works
The pill prevents the ovaries from releasing an egg each month (ovulation). It also:
- thickens the mucus in the neck of the womb, so it is harder for sperm to penetrate the womb and reach an egg
- thins the lining of the womb, so there is less chance of a fertilised egg implanting into the womb and being able to grow
Types of combined pill
Although there are many different brands of pill, there are three main types:
- Monophasic 21-day pills (the most common type). Each pill has the same amount of hormone in it. One pill is taken each day for 21 days and then no pills are taken for the next seven days. Examples are Microgynon, Brevinor and Cilest.
- Phasic 21-day pills. Phasic pills contain two or three sections of different coloured pills in a pack. Each section contains a different amount of hormones. One pill is taken each day for 21 days and then no pills are taken for the next seven days. Phasic pills need to be taken in the right order. Examples are Binovum and Logynon.
- Every Day (ED) pills. There are 21 active pills and 7 inactive (dummy) pills in a pack. The two types of pill look different. One pill is taken each day for 28 days with no break between packets of pills. Every Day pills need to be taken in the right order. Examples are Microgynon ED and Logynon ED. Follow the instructions that come with your packet. If you have any questions about how to take the pill, ask your GP, practice nurse or pharmacist. It's important to take the pills as instructed because missing pills or taking them at the same time as certain medicines may make them less effective.
Where you can get the pill
You can get the pill from:
Contraception services are free and confidential for women and men of all ages, including for people under the age of 16 through the NHS.
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 that 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.
How to take the pill
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Starting the first pack of pills
The combined oral contraceptive pill (the pill) can be started at any time in your 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 and will not need additional contraception.
If you start the pill up to and including the fifth day of your period, you will still 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 seven days.
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.
Taking pill packs back to back
For monophasic combined pills (pills all the same colour and with the same level of hormones), it is normally fine to start a new pack of pills straight after your last one, for example if you want to delay your period for a holiday.
However, avoid taking more than two packs together unless advised to by your GP or Nurse. This is because the womb lining continues to build up and you may have breakthrough bleeding as it sheds slightly. Also, some women find they feel bloated if they run several packs of the pill together.
After having a baby
If you have just had a baby and are not breastfeeding, the pill can be started on day 21 after the birth. You will be protected against pregnancy straight away.
If you start the pill later than 21 days after giving birth, you will need to use additional contraception (such as condoms) for the next seven days.
If you are breastfeeding a baby under six months old, taking the pill can reduce your flow of milk. It is recommended that you use a different method of contraception until you stop breastfeeding.
After a miscarriage or abortion
You can start taking the combined pill immediately after a miscarriage or abortion. Ask your doctor for advice on when you will be protected from pregnancy, as you may need to use extra contraception, such as condoms for a short time.
How to take the pill
- Take your first pill from the packet marked with the correct day of the week, or the first pill of the first colour (phasic pills).
- Continue to take a pill at the same time each day until the pack is finished.
- Stop taking pills for seven days (during these seven days you will get a bleed).
- Start your next pack of pills on the eighth day, whether you are still bleeding or not. This should be the same day of the week as when you took your first pill.
Every day pills
- Take the first pill from the section of the packet marked ‘start’. This will be an active pill.
- Continue to take a pill every day, in the correct order and preferably at the same time each day, until the pack is finished (28 days).
- During the seven days of taking the inactive pills, you will get a bleed.
- Start your next pack of pills after you have finished the first, whether you are still bleeding or not.
Vomiting and diarrhoea
If you vomit within two hours of taking a pill, it may not have been fully absorbed into your bloodstream. Take another pill straight away and the next pill at your usual time. You should still be protected from pregnancy.
However, if you continue to be sick, while you are ill and for two days after recovering as you may not be protected from pregnancy.
Very severe diarrhoea (six to eight watery stools in 24 hours) may also reduce the effectiveness of the pill. 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 family planning nurse or call NHS Direct Wales (0845 46 47) if you are unsure, or if your sickness or diarrhoea continue.
Who can use it?
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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, not everyone can use the combined oral contraceptive pill (the pill). You will need to talk to your doctor or nurse about your medical history to find out if the pill is right for you.
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
- breast cancer
- disease of the gallbladder or liver
- diabetes with complications or diabetes for the last 20 years
Some advantages of the pill include:
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- It does not interrupt sex.
- It usually makes your bleeds regular, lighter and less painful.
- It reduces your risk of cancer of the ovaries, womb and colon.
- It can reduce the symptoms of premenstrual syndrome.
- It can sometimes reduce acne.
- It may protect against pelvic inflammatory disease.
- It may reduce the risk of fibroids, ovarian cysts and non-cancerous breast disease.
Some disadvantages of the pill include:
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- It can cause temporary side effects at first, such as headaches, nausea, breast tenderness and mood swings. If these do not go after a few months, it may help to change to a different pill.
- It can increase your blood pressure.
- It does not protect you against sexually transmitted infections.
- Breakthrough bleeding and spotting is common in the first few months of using the pill.
- It has been linked to an increased risk of some serious health conditions such as thrombosis (blood clots) and breast cancer.
Missing a pill/pills or starting a pack late 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.
What to do if you miss a pill or pills
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 condoms, and 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 – see below
- you may need to start the next pack of pills without a break – see below
You may need emergency contraception if you have had unprotected sex in the previous seven days and have missed two or more pills (more than 48 hours late) in the first week of a pack.
Get advice from your contraception clinic, doctor or pharmacist about this. You can also call NHS Direct Wales on 0845 46 47 (24 hours a day).
Starting the next pack after missing two or more pills
If there are seven or more pills left in the pack after the last missed pill:
- finish the pack
- have the usual seven-day break
If there are fewer than seven pills left in the pack after the last missed pill:
- finish the pack and start the new one the next day, without having a break
Find sexual health services near you.
The pill is less effective when…
- it is not taken according to the instructions
- it does not stay in the body long enough to work, for example because of vomiting or diarrhoea
- other medicines make it less effective
Am I protected from pregnancy during the seven-day break or when taking inactive pills?
If you have taken all your pills correctly and nothing else has happened to you to make the pill less effective (such as vomiting), you are protected from pregnancy during the seven-day break or when taking inactive pills.
If you’re on the combined pill Qlaira and you’ve missed a pill, see the manufacturer’s Qlaira patient information leaflet on the electronic Medicines Compendium website or get advice.
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The combined oral contraceptive pill (the pill) is generally well tolerated, but there are some possible side effects.
Breakthrough bleeding and spotting is common in the first few months of taking the pill.
Other temporary side effects may occur after first starting the pill, including:
- breast tenderness and breast enlargement
- mood changes
- an increased or decreased libido (sex drive)
- fluid retention
- rise in blood pressure
If these do not stop within a few months, changing the type of pill may help.
There is no evidence that the pill causes women to gain weight.
Reporting side effects
The Yellow Card Scheme allows you to report suspected side effects from any type of medicine that you are taking. It is run by a medicines safety watchdog called the Medicines and Healthcare Products Regulatory Agency (MHRA). See the Yellow Card Scheme website for more information.
Interactions other medicines
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The combined contraceptive pill (the pill) can interact with other medicines. Some of the more common interactions are listed below. However, this is not a complete list.
If you want to check that your medicines are safe to take with the pill, ask your doctor or pharmacist, or read the patient information leaflet that comes with your medicine.
The following antibiotics rifampicin and rifabutin (which can be used to treat illnesses including tuberculosis and meningitis) can reduce the effectiveness of the pill. Other antibiotics do not have this effect.
Long-term rifampicin or rifabutin
If you are going to be taking rifampicin or rifabutin for over two months, you may want to consider starting or changing to a contraception method that is not affected by these medicines. For example:
Short-term rifampicin or rifabutin
If you are taking rifampicin or rifabutin for less than two months and want to continue with your same combined contraceptive pill, you must discuss this with your doctor or specialist nurse. They will be able to get detailed up-to-date guidance from the Faculty of Sexual and Reproductive Healthcare.
You may need to use additional contraception (such as condoms) while you are taking the antibiotics and for 28 days after finishing the course. You may also need to change to a higher strength pill and take your pill in a different way from usual. You will need to continue this for 28 days after finishing the course.
Your GP will be able to give you further advice.
The combined pill can interact with medicines called enzyme inducers, which speed up the breakdown of progestogen by your liver, reducing the effectiveness of the pill.
Examples of enzyme enducers include:
- the epilepsy drugs carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone and topiramate
- St John’s Wort (a herbal remedy)
- 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 you are taking one of these medicines.
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There are some risks associated with using the combined contraceptive pill (the pill). However, these risks are small. For most women, the benefits of the pill outweigh the risks.
The oestrogen in the pill may cause your blood to clot more readily. If a blood clot develops, it could cause a deep vein thrombosis (clot in your leg), pulmonary embolus (clot in your lung), stroke or heart attack.
The risk of getting a blood clot is very small, but your doctor will check if you have certain risk factors that make you more vulnerable before prescribing the pill.
The pill can be taken with caution if you have one of the risk factors below, but should not be taken if you have two or more risk factors.
Risk factors include:
- being over 35 years old
- being a smoker or having quit smoking in the last year
- being very overweight (the pill should not be taken if your BMI is over 35 because the risks of taking the pill usually outweigh the benefits)
- having migraines (you should not take the pill if you have severe or regular migraine attacks, especially if you get aura or a warning sign before an attack)
- having high blood pressure
- having had a blood clot or stroke in the past
- having a close relative who had a blood clot when they were younger than 45
- being immobile for a long time, for example in a wheelchair or with a leg in plaster
Research is ongoing into the link between breast cancer and the pill. Research suggests that users of all types of hormonal contraception have a slightly higher chance of being diagnosed with breast cancer compared with women who do not use them. However, 10 years after you stop taking the pill, your risk of breast cancer goes back to normal.
Research has also suggested a link between the pill and the risk of developing cervical cancer, and a very rare form of liver cancer.
However, the pill does offer some protection against developing cancer of the endometrium (lining of the womb), ovarian cancer and colon cancer.
The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Will antibiotics stop my contraception working?
It depends on which type of contraception you’re using.
It’s now thought the only types of antibiotic that interact with hormonal contraception and make it less effective are rifampicin and rifabutin (which can be used to treat illnesses including tuberculosis and meningitis).
If you are prescribed rifampicin or rifabutin, you may need additional contraception (such as condoms) while taking the antibiotic. Speak to your doctor or nurse for advice.
When you take two or more medicines at the same time, the effects of one medicine can be altered by the other. This is known as an interaction. Some antibiotics can interact with some forms of hormonal contraception.
There are several types of hormonal contraception, such as:
- combined contraceptive pill
- progestogen-only contraceptive pill
- contraceptive implants and injections
- intrauterine system (IUS)
- contraceptive patch
- vaginal ring
- emergency contraception
If you’re using hormonal contraception, it’s important to understand that some medicines can reduce its effectiveness. This includes some types of antibiotic. If this happens, to avoid getting pregnant you’ll need to use additional contraception, such as condoms, change to a different method of contraception, or take your contraception in a different way. See below for more details.
If you’re not sure if your contraception is affected by other medicines, speak to your GP or pharmacist or call NHS Direct Wales on 0845 4647.
Rifampicin-like medicines are the only types of antibiotic that can make hormonal contraception less effective. This includes:
These types of medicine can increase the enzymes in your body. This is known as enzyme-inducing and can affect hormonal contraception.
Enzymes are proteins that control your body’s chemical reactions. Enzyme-inducing antibiotics speed up the processing of some contraceptive hormones and therefore reduce the levels of these hormones in your bloodstream. This makes the contraceptive less effective.
Apart from those mentioned above, all other antibiotics are not enzyme-inducing.
If you’re going to take rifampicin or rifabutin for over two months, you may want to consider starting or changing to a contraception method that’s not affected by these medicines if you’re currently using the:
- combined pill
- progestogen-only pill
- vaginal ring
Contraception methods that aren’t affected by rifampicin or rifabutin include:
- progestogen injection
- intrauterine device (IUD)
If you’re taking rifampicin or rifabutin for less than two months and want to continue your same hormonal contraception, you must discuss this with your doctor. You may be asked to take this contraception in a different way from usual and use condoms as well. You will need to continue this for 28 days after finishing the antibiotics.
If you’re taking antibiotics other than rifampicin or rifabutin, you don’t normally need to use additional contraception.
However, if the antibiotics, or the illness they are treating, cause diarrhoea or vomiting, your oral hormonal contraception may be affected. For more information, see below.
What if I’m on the pill and I’m sick or have 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 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 Direct (0845 46 47) for more information, or if your sickness or diarrhoea continues
Missing pill or pills or starting a new pack late can make your pill less effective at preventing pregnancy. You may need to use extra contraception such as condoms. You may also need emergency contraception. The advice depends on:
- when you missed the pills (where in the packet you are)
- how many pills you’ve missed
For advice on what to do if you’ve missed a pill, see:
If you’re on the combined pill Qlaira and you’ve missed a pill, see the manufacturer’s Qlaira patient information leaflet on the electronic Medicines Compendium website or get advice. ^^ Back to top
Last Updated: 11/09/2014 13:40:21