The contraceptive pill is one of the most common forms of contraception, but it’s important to be aware of the side effects


What are contraceptive pills?


Contraceptive pills are small tablets that you take every day or for 21 days at a time (depending on the type of pill) to help prevent you from becoming pregnant, or sometimes to help those who struggle with difficult menstrual cycles. They work by regulating your hormones, putting you more in control of your body.


There are two main types of contraceptive pills, the combined pill and the progestogen-only pill. 


Your GP, nurse or pharmacist can help you find which type of pill is the most suitable for you. Alternatively, access the Boots Online Doctor – Contraceptive Pill service* for advice and a prescription, if appropriate.



Combined pill


Often just called “the pill”, it contains artificial versions of the female oestrogen and progestogen hormones. 


It works by stopping the ovaries from releasing an egg (ovulating) each month, and by making it harder for an egg to get fertilised by sperm and attach to the wall of the uterus.


You’ll usually need to take one pill at the same time every day for 21 days, then you take a break for seven days before taking the pill again. During this break, you will have a bleed like a period. There are different types of combined pills, and some can be taken without needing a break. Always make sure you read the instructions that come with your pack.


When taken correctly, the combined pill is over 99% effective at preventing pregnancy.


Who can take the combined pill?


The combined pill isn’t suitable for everyone. It may not be right for you 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 or have certain medical conditions


To find out whether the combined pill is suitable for you, talk to your GP, nurse or pharmacist, or access the Boots Online Doctor – Contraceptive Pill service.* 


If there are no medical reasons why you can’t take the combined pill, and you don’t smoke, you can take it until your menopause. Your prescriber will check that it remains suitable for you, which will involve having your blood pressure and weight checked every 12 months.


What are the side effects of the combined pill?


Side effects of the combined pill vary from person to person. Minor side effects can include:


• Headaches
• Nausea
• Breast tenderness
• Mood swings
• Irregular bleeding


If any of these side effects don’t go after a few months and you’re concerned, it may help to speak to your GP about changing to a different pill.


There are some serious side effects associated with using the combined pill. These are low risk and can include:


Blood clots


The oestrogen in the combined pill may cause your blood to clot more readily. If a blood clot develops, it could cause:


• Deep vein thrombosis (clot in your leg)
• Pulmonary embolus (clot in your lung)
• Stroke
• Heart attack


The risk of getting a blood clot is very small, but your doctor will check if you have certain risk factors before prescribing the combined pill.


Cancer


The combined pill can slightly increase the risk of developing breast cancer and cervical cancer. However, 10 years after you stop taking the pill, your risk of breast cancer and cervical cancer returns to normal.


If you have any concerns, you should discuss these with a healthcare professional, such as your GP or pharmacist.


For full information of a medicine’s side effects, it’s important to read the Patient Information Leaflet that comes with your pack.



Progestogen-only pill


Commonly known as the “mini pill”, it only contains the female hormone, progestogen.


There are two different types:


• Traditional progestogen-only pill, which must be taken within three hours of the same time each day. It thickens the mucus in the cervix to stop sperm from reaching an egg.

• Desogestrel progestogen-only pill, which must be taken within 12 hours of the same time each day. It thickens the mucus in the cervix to stop sperm from reaching an egg and, unlike the traditional progestogen-only pill, it can also stop ovulation.


The progestogen-only pill needs to be taken every day and at the same time each day. Not taking the pill at the right time, missing pills or taking the pill alongside other medicines can reduce its effectiveness. Always follow the instructions that come with your pill packet.


If taken correctly, it's more than 99% effective at preventing pregnancy.


Who can take the progestogen-only pill?


The progestogen-only pill is generally good for women who can’t take contraception containing oestrogen (the combined contraceptive pill, for example). However, you may not be able to take the progestogen-only pill if you:


• Think you might be pregnant
• Don’t want your periods to change
• Take other medicines that may affect the pill
• Have unexplained bleeding in between periods or after sex
• Have developed arterial disease, or heart disease, or have had a stroke
• Have liver disease
• Have breast cancer or have had it in the past
• Have severe cirrhosis or liver tumours 


To find out whether the progestogen-only pill is right for you, talk to your GP, nurse or pharmacist, or access the Boots Online Doctor – Contraceptive Pill service.* 


If you're healthy and there are no medical reasons why you shouldn’t take the progestogen-only pill, you can take it until your menopause, or until you're 55. Your prescriber will check that it remains suitable for you.


What are the side effects of the progestogen-only pill?


The progestogen-only pill is generally well tolerated and side effects are rare. If you do experience side effects, they can include: 


• Acne
• Breast tenderness and breast enlargement
• An increased or decreased sex drive
• Mood changes
• Headaches and migraines
• Nausea or vomiting
• Small fluid-filled sacs (cysts) on your ovaries – these are usually harmless and disappear without treatment


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. 


Like with the combined pill, there are some risks associated with using the progestogen-only pill. These risks are low and can include:


Ovarian cysts


There’s a chance you could develop fluid-filled cysts on your ovaries. These aren’t dangerous and don’t usually need to be removed.


In many cases, the cysts don’t cause symptoms, although you may experience pelvic pain. They tend to disappear without treatment.


Breast cancer


Research is continuing into the link between breast cancer and the progestogen-only pill. Currently, there isn’t enough evidence to say for certain that the progestogen-only pill doesn’t increase the risk of breast cancer.


But if there is any increased risk, it's likely to be very small and disappear with time after you stop taking the progestogen-only pill.


If you’re concerned, you should speak to a healthcare professional, such as your GP or pharmacist.


For full information of your medicine’s side effects, it’s important to read the Patient Information Leaflet that comes with it.


If you have concerns or questions about your contraceptive pill, speak to your prescriber.

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*Access to prescription only medicine is subject to a consultation with a clinician to assess suitability. Charges apply.