Side Effects of the Contraceptive Pill

Dr Kathryn Basford

Medically reviewed by

Dr Kathryn Basford

Last reviewed: 13 Jan 2022

When you take a contraceptive pill, there’s a chance you might get side effects. Some side effects are more common than others, and there are ways to get around them. And most of the time, side effects from contraceptive pills are temporary. But if something does not feel quite right, always speak to a doctor about it.

2 women walking in the city talking about the side effects and their contraceptive pills

Contraceptive pills contain one or two types of female sex hormones, oestrogen and progesterone. These are similar to the hormones your body naturally produces. You’ll have both types of hormones in a combined pill or only progesterone in a mini pill.

In this guide, we go through the side effects of combined pills and mini pills. Whether you’re thinking about taking the pill or want to switch to an alternative birth control method, we’ve got you covered.

Common side effects of the contraceptive pill

Common side effects of the contraceptive pill usually occur during the first few months you start taking the pill and should go away after a little while. About 1 in 10 women get these common side effects:

  • irregular bleeding
  • feeling sick (nausea)
  • short term weight gain
  • breast tenderness or swelling
  • acne

Irregular bleeding

While your body gets used to the contraceptive pill, you may experience irregular bleeding, such as:

  • bleeding outside of your 7 day break on the combined pill
  • bleeding any time during your cycle on the mini pill

This type of irregular bleeding is also known as ‘breakthrough bleeding’ and it should stop a few months after you start your pill. If you bleed for longer than 7 days or bleed heavily, you should speak to a doctor as soon as you can. It could be a sign that you need to switch to another type of contraception, or you need to have a health check to find out what’s causing the bleeding.

Feeling sick (nausea)

The contraceptive pill might make you feel sick or vomit. If you vomit within 2 hours of taking your pill, you are not protected against pregnancy. You should take another pill or use another form of contraception.

If your nausea does not go away after a few months, you should speak with a doctor to switch to a different pill. You can try:

  • taking a low oestrogen pill, like Gedarel
  • taking an oestrogen-free pill (mini pill), such as Cerazette
  • non hormonal birth control, such as condoms or a copper IUD

Short term weight gain

There is a chance you might gain weight when you start taking the pill. This weight gain is temporary and it’s usually because your body is getting used to the hormones in the pill. Other than that, there is no direct link between long term weight gain and the pill.

Hormones in the pill can cause water retention which can make you feel bloated or look like you’ve put on weight. Any extra weight should be gone within 3 to 6 months, and you can keep it at bay by:

  • exercising 5 times a week, for at least 30 minutes at a time
  • choosing to drink water instead of sugary drinks
  • eating low salt foods, to prevent water retention
  • getting between 7 to 9 hours of sleep every night

Breast tenderness or swelling

When you start taking the contraceptive pill, you may have some breast tenderness or swelling. This can be due to water retention from the hormones in the pill.

If the tenderness or swelling does not improve after a few months, see a doctor.

You should get into the habit of checking your breasts for lumps, dimples or skin colour changes too. If you notice any other changes, such as discharge from your nipples, get checked by a healthcare professional right away.


Acne is more common as a side effect if you’re taking the mini pill, so you might be able to switch to the combined contraceptive pill if it is safe for you.

If you continue to get acne as a side effect, you might want to consider using a non hormonal method of contraception.

But if you want to stay on the pill, there are effective treatments for acne that you can try with the advice of a doctor.

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Less common side effects of the contraceptive pill

There are less common side effects of the contraceptive pill, and there’s a much smaller chance you will get them. These side effects should get better after the first few months of you taking your pill:

  • mood changes
  • headaches
  • reduced sex drive

Mood changes

You might experience having a low mood or start getting mood swings due to the hormones in the pill. At the moment, there is no direct link between the pill and mood changes because there can be other reasons why your mood might be changing.

You may want to consider keeping a journal to keep track of your wellbeing and then following this up with regular sessions with a therapist.

If you start to feel more unhappy over time or start having negative thoughts, you can reach out to a doctor for help on how to maintain your mental health.


Getting a headache every now and again is normal, but if you’re on the pill you might start to have:

  • headaches more often
  • stronger headaches, which are more painful or affect your vision
  • headaches that last a long time

You’re more likely to get headaches if you already get migraines or you’re on the combined pill. If you start to have new migraines while using a combined pill, you should stop taking the pill and speak to a doctor. As soon as you start getting headaches that do not go away with painkillers, you must see a doctor.

You may need to:

  • switch to a low oestrogen combined pill
  • switch from a combined pill to a mini pill
  • stop taking the pill and use non hormonal birth control methods

Headaches can be a sign of other side effects, such as your blood pressure increasing. So it’s important to go for regular blood pressure checks when you start the pill.

Reduced sex drive

When you start taking the pill, you may notice changes in your libido and you may not feel like having sex as often as you used to. Having a reduced sex drive can be due to other reasons such as:

  • feeling stressed or tired
  • not getting enough sleep
  • taking certain medication
  • tension between you and your partner

If your sex drive does not go back to normal, you may want to speak to a doctor about switching to a different pill or using a non hormonal method to prevent pregnancy.

Which side effects require medical attention?

Combined contraceptive pills can increase the risk of getting a blood clot in a vein or artery. You should see a doctor immediately if you notice:

  • painful swelling in a leg or both legs
  • sudden problems seeing or speaking
  • sharp chest pain when breathing, difficulty breathing or coughing blood
  • a new or worse headache or migraine
  • weakness or numbness in an arm or leg

What are the side effects of stopping the contraceptive pill?

You may experience side effects when stopping the contraceptive pill and these include:

  • acne - while being on the combined pill reduces acne, coming off of it might make it come back
  • cramps - the pill can help reduce period pains, so coming off of it can make your cramps more painful
  • heavy or irregular periods - your first few periods after coming off the pill may be heavier or more irregular than when on the pill

These side effects should get better after the first few months of stopping the pill as you get back to your normal period cycles.

Remember that when you come off the pill you are no longer protected from getting pregnant. You will need to use alternative birth control methods.

How safe is the contraceptive pill?

Because the pill has been around for a long time (decades) we know a lot about them, so you can get the right advice on which pill is the safest for you to use. This makes the contraceptive pill relatively safe for most women, compared to new medicines that have just come out recently.

To make sure you’re safe while you use the pill, you do need to go for regular blood pressure checkups with your doctor or at a pharmacy. You should also check your breasts regularly, and look out for anything else that might be unusual for your body.

When you’re on the pill, your chances of getting side effects can increase if you’re over 35 years old, overweight, have certain medical conditions or smoke.

Each type of birth control is different, and you may want to weigh up the pros and cons with your doctor to determine which method is best for you.

You can switch to another type of birth control pill or other non hormonal methods if you need to, and a doctor can advise you on the safest way to do this.

Keep in mind that the contraceptive pill does not protect you from getting sexually transmitted infections (STIs), so use a condom or other barrier method to practise safe sex.

How to choose a contraceptive pill

When you choose a contraceptive pill, you should think about:

  • your age - if you are over 35 years old you can consider using the combined pill if you do not smoke, otherwise you should use the mini pill
  • your weight - being overweight might mean you should go for the mini pill rather than the combined pill
  • any health conditions you have - if you have a health condition such as high blood pressure or regularly get migraines, the mini pill might be a better option than the combined pill
  • any health conditions that run in your family - if members of your family have ever had a blood clot, a heart attack or cancer in the past, you may want to go for the mini pill, or non hormonal birth control
  • whether you are a smoker - if you smoke and are over 35 years old, you may be offered the mini pill, otherwise, you can use the combined pill
  • if you’ve been on the pill before - think about the last time you used the pill, and whether you want to use the same pill or try something new
  • any medication you currently take - you will need to tell your doctor if you take any other medication, just in case they interact with the pill you want to use

Going through all these factors with a doctor will help you choose which contraceptive pill is right for you.

Alternatives to the contraceptive pill

There are many alternatives to the contraceptive pill. These are useful if you do not want to take a pill every day or if you want a long term birth control method.

You can choose from:

  • other types of hormonal contraception
  • hormone-free copper IUD (intrauterine device)
  • non hormonal barrier methods

Hormonal contraceptives

There are different types of hormonal contraceptives. These include:

  • hormonal IUD, which is inserted into the womb and can last a few years
  • hormonal implant, which is placed under your skin and can last a few years
  • hormonal injection, where you get one injection that gives you a few months of protection against pregnancy
  • contraceptive patch, such as Evra, which you change once a week
  • vaginal ring, which you insert in your vagina once a month

Each of these methods releases hormones into your body, protecting you from pregnancy.

The IUD (intrauterine device; copper coil)

The IUD (intrauterine device), also known as the copper coil, is placed into your uterus (womb) by a trained doctor or nurse. It’s hormone-free and works as soon as it’s put in.

An IUD is made of copper, which is slowly released into your womb to stop a fertilised egg from attaching to the lining of your womb. This prevents you from getting pregnant even if you have unprotected sex and is effective for 5 to 10 years.

Barrier methods

You can use barrier methods that are hormone-free to protect yourself from pregnancy. You need to put them on before having sex, and they prevent sperm from getting into your womb so you do not get pregnant.

Barrier methods include:

  • male condoms, which you put on a man's penis
  • female condoms, which you put inside the vagina
  • contraceptive diaphragm with spermicide, which fits over the cervix
  • contraceptive cap with spermicide, which fits into the cervix

If you notice that any of these methods have ripped or come loose during sex, you may need the morning after pill.

Medically reviewed by:
Dr Kathryn Basford Accreditations: MB, ChB, MPH

Dr Kathryn Basford is a qualified GP who works as a GP in London, as well as with ZAVA. She graduated from the University of Manchester and completed her GP training through Whipps Cross Hospital in London.

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Last reviewed: 13 Jan 2022

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