Side Effects of the Contraceptive Pill

While the contraceptive pill is the most common method of contraception used in the UK, it is still associated with various side effects. Different types of pills have different side effects, and not everyone who takes the pill will get them. Here, we’ll explore some of the common side effects of the contraceptive pill, why they might occur, and what you can do about them.

What Are the Side Effects of the Contraceptive Pill?

There are a variety of common and rare side effects that you can get while taking the pill. These will vary from person-to-person and will also depend on the type of pill you're taking. It’s important to remember that every person’s experience of taking the contraceptive pill will be different.

Spotting between periods

Irregular bleeding or spotting between periods is a common side effect from taking the pill, especially during the first few months. That’s because your body is getting used to the change in hormone levels it causes, and it will likely stop once your body has adjusted. It can also happen if you:

  • miss your pill
  • experience throwing up or diarrhoea while on the pill

If you miss your pill, or you vomit or have diarrhoea which can prevent your body from absorbing the pill, your body might respond by shedding some uterine tissue before your next period, causing spotting.

Some research shows that 40% of women who take the mini pill or progesterone-only pill will experience irregular bleeding. Breakthrough bleeding can occur with any type of hormonal contraception but is more likely in women who use low-dose or ultra-low-dose combined pills.

You should speak to your doctor if the spotting episode:

  • lasts for a week or more
  • is heavy
  • gets worse


Feeling sick (nausea) is one of the most commonly reported side effects of the contraceptive pill. It’s often mild and is more common in the first few days or weeks of taking the pill. Nausea usually goes away on its own as your body adjusts to the change in hormone levels.

Oestrogen may cause nausea, particularly in higher doses, because it can irritate the stomach lining. Some studies have also shown that oestrogen can slow the emptying of the stomach by relaxing its muscles, which can also make you feel sick.

If you experience nausea while taking the pill, there are several things you can try to help you feel better:

  • take your pill with food
  • get some fresh air by going for a walk outside or opening a window
  • distract yourself by listening to music, watching a film, or doing an activity you enjoy
  • take regular sips of a cold drink, like chilled water
  • ginger or peppermint herbal teas
  • eat foods that contain ginger such as ginger biscuits
  • eat smaller, more frequent meals
  • apply pressure to certain areas of the wrist, called acupressure

Weight gain

Although there is some speculation that hormonal contraception, including the oral contraceptive pill, causes weight gain, there is very little evidence to prove this. Some women may experience temporary weight gain when they first start taking the pill, but this is likely to be because of water retention rather than an increase in fat.

A 2014 literature review found no significant effect of combined contraceptives on weight. The authors of the review found this to be the case across all types of pills but concluded there was a lack of well-conducted research to be sure.


While migraines can be a side effect of taking the pill, some contraceptive pills can also be used to help treat migraines. This is because migraines can be caused by hormonal changes, and the pill can help regulate your hormones if that’s what’s causing your migraines. Alternatively, the change in hormones caused by starting the pill can lead to migraines. Due to this, you may be advised against taking combined pills by your doctor if you have a history of migraine headaches.

The combined hormonal contraceptive pill is also associated with a greater risk of having a stroke. This risk is further increased if you also experience migraines with aura.

Vaginal discharge

Taking the contraceptive pill thickens your cervical mucus to help prevent sperm from entering the uterus. You may notice that your vaginal discharge is thicker or whiter when on the pill. These changes are normal but if you notice the following you should speak to your doctor or nurse for advice:

  • a fishy or rotten meat-like odour
  • cottage cheese-like texture
  • green, yellow, brown, or pink colour changes
  • there’s more discharge than usual

Decreased libido

There is conflicting evidence about how the contraceptive pill affects your libido (sex drive). Some studies point to the pill increasing libido, while others say it’s more likely to decrease it.

Changes in hormone levels are the reason why the contraceptive pill may affect your libido. The pill is designed to stop ovulation, the release of an egg from the ovaries, to prevent pregnancy. Even if you do not have a monthly period your ovaries still function and produce the hormone testosterone which helps to regulate your sex drive. The oestrogen in the combined oral contraceptive pill can cause less testosterone to circulate, keeping your hormones at stable levels. So, if you experienced an increased sex drive around the time of your period before taking the pill, you may notice this has levelled out.

If you have noticed a decrease in your sex drive, try:

  • talking to your partner by letting them know you’ve noticed changes in your libido – you could also discuss the things you enjoy sexually to help you get intimate
  • something new like role-playing, experimenting with sex toys, or even reading erotic fiction to help get you in the mood
  • exploring your body through masturbation to find out what feels good for you
  • talking to a medical profession to rule out any medical causes or to discuss other methods of contraception which may have less of an effect on your libido

Breast pain or tenderness

Breast pain or tenderness is another common side effect of the contraceptive pill. These side effects are more common in women who use the combined pill. Combined pills slightly increase the risk of developing breast cancer, but the risk level returns to normal when the pill is stopped. Painful breasts are not usually a sign of breast cancer but painful lumps can be, so it is important to examine your breasts regularly and report any changes to your doctor.

Which Side Effects Require Medical Attention?

While most side effects of the pill are temporary and harmless, there are some symptoms you should not ignore.Speak to your doctor immediately if you experience:

  • painful swelling in your leg
  • jaundice (yellowing of eyes or skin)
  • sudden pain in the chest
  • a sudden cough
  • difficulty breathing
  • a migraine for the first time
  • an unusually severe migraine
  • numbness in any body part
  • blurred vision or impaired vision
  • difficulties with your speech
  • fainting and dizziness or seizures
  • swellings of the face, tongue or throat
  • breast lumps
  • changes to your nipples
  • unusual vaginal discharge or bleeding
  • pain during sex or pelvic pain
  • severe abdominal pain
  • raised blood pressure readings
These side effects are rare to very rare, but they can indicate a serious condition such as an allergic reaction, a problem with your liver, or cancer. If you suffer from any abnormal side effects which bother you, you should always discuss them with a doctor.

Which Contraceptive Pill Has the Least Side Effects?

In general, people experience fewer side effects when taking the mini-pill because it does not contain oestrogen. But this kind of pill may not be right for everyone. All oral contraceptive pills are as effective as one another at preventing pregnancy when taken correctly, but some may be more suitable for you than others.

Mild side effects are usually only temporary and are more likely to occur when you first start taking the pill. As your body adjusts to the hormones, the effects are likely to go away on their own. If you are still experiencing side effects after 3 months, or you’re finding them difficult to deal with, speak to your doctor about other options.


Due to the lack of oestrogen, mini-pills are associated with fewer side effects. But they can cause temporary side effects when you first start using them, such as:

  • acne
  • breast tenderness
  • headaches
  • spotting or irregular bleeding
  • weight changes

Combined pill

The combined pill contains two man-made versions of the hormones, progesterone and oestrogen. Because the combined pill contains oestrogen, it can cause oestrogen-related side effects such as headaches, nausea, mood swings and breast tenderness. Taking a contraceptive pill that has a lower dose of oestrogen (30mcg or less) can help to reduce the risk of side effects.

What Health Risks Are Associated With Taking the Contraceptive Pill?

Although contraceptive pills are safe, taking the combined contraceptive pill can increase your risk of certain health problems.

Contraceptive pill and cancer

The contraceptive pill has been associated with an increased risk of developing cancer, but this increase is usually small. This risk is also completely reduced after discontinuing the pill. Studies have shown the pill can cause:

  • a possible small increased risk of breast cancer, which declines within 5 to 10 years of stopping treatment.
  • a possible small increased risk of cervical cancer, which declines within 5 to 10 years of stopping treatment

The contraceptive pill can also reduce the risk of certain cancers. Studies have shown the pill can:

  • reduce the long-term risk of ovarian cancer
  • reduce the long-term risk of endometrial cancer
  • reduce the risk of colorectal cancer

Contraceptive pill and thrombosis (blood clots)

The use of the combined pill is linked with a slightly increased risk of developing a blood clot. The risk of thrombosis is around 3 times higher in people who use the combined pill compared to those who don’t, but that is still a low risk for most people.

It is the oestrogen in the combined pill that can cause your blood to clot more easily and could increase your risk of a:

  • blood clot in your lung (pulmonary embolism)
  • blood clot in your leg (deep vein thrombosis)
  • heart attack
  • stroke

If you are already at a higher risk of developing a blood clot, or you’ve had blood clots in the past, your doctor may recommend a different type of contraception, like the mini pill.

Contraceptive pill and high blood pressure

Contraceptive pills that contain oestrogen may slightly increase your risk of high blood pressure. If you already have high blood pressure or are at a greater risk, then a combined pill could increase your risk of having a heart attack or stroke.

You can help to lower your risk of heart attacks or stroke, or lower your blood pressure by making simple lifestyle changes, such as:

  • following a healthy, well-balanced diet
  • reducing your exposure to stress
  • taking part in regular exercise

Contraceptive pill and gallbladder disease

Research shows that there is an increased risk of gallbladder disease in women who use oral contraceptives for a long time compared to those who don’t. Evidence suggests that both progesterone and oestrogen increase the chance of gallstones.

Is the Pill Safe for Everyone?

When you speak to your doctor or nurse about starting a contraceptive pill they will ask about:

  • your medical history
  • any medications you take
  • your family history
  • whether you smoke
  • your lifestyle

They will also check your blood pressure, weight, and height. The contraceptive pill is not safe for everyone to take and your doctor will discuss with you which pill is safest for you, or an alternative form of contraception you can use, such as the intrauterine device (copper coil).

Alternatives to the Contraceptive Pill

If you are worried about the side effects of the contraceptive pill, or you’re finding them difficult to live with, there are alternatives to the oral contraceptive pill that you can try.

Non-hormonal contraception

A non-hormonal birth control alternative is the intrauterine deceive (IUD) also known as the copper coil. It is a small T-shaped device made from plastic and copper that is inserted into your womb by a doctor or nurse.

The IUD prevents pregnancy by releasing copper, which stops sperm from being able to survive in your cervix and potentially fertilise an egg. It can be fitted at any time during your menstrual cycle, can protect you from pregnancy for 5 to 10 years, and is 99% effective.

Barrier methods

There are several barrier methods of contraception available. Barrier methods work by stopping sperm from reaching an egg and some methods, like male condoms, can also protect against sexually transmitted infections (STIs). Other barrier methods include:

  • female condoms also known as a Femidom
  • the diaphragm
  • the cervical cap

Hormonal contraception

As well as the contraceptive pill, there are other types of hormonal contraception available. Because these contain hormones, there is a chance they may cause hormone-related side effects. These contraceptives include:

  • injections – a contraceptive injection that contains progestogen only and releases this hormone into your bloodstream to prevent pregnancy. It lasts for 8 to 13 weeks depending on which one you are given. The injection is over 99% effective at preventing pregnancy and is useful for women who find it difficult to remember to take a daily pill.
  • implants – the contraceptive implant contains the hormone progestogen. It is a small plastic rod that is placed under the skin of your upper arm by a doctor or nurse and lasts for 3 years. The implant is useful for women who may not be able to use contraception containing oestrogen, but it can cause your periods to become irregular, lighter, heavier, or longer, or to stop altogether.
  • patchesthe contraceptive patch is a small sticky patch that is stuck directly to your skin. You wear the patch for 7 days before changing for a new one on day 8, and you do this for 3 weeks and then have a patch-free week. The patch contains the same hormones as the combined pill, oestrogen and progestogen, so it may not be suitable for you if you have experienced side effects on the combined pill.
  • vaginal rings – a small, plastic ring that is placed inside the vagina and delivers a continuous dose of oestrogen and progestogen into your bloodstream. It is more than 99% effective and one ring provides contraception for one month. Because it contains the same hormones as the combined pill, the vaginal ring may cause similar hormone-related side effects.
  • hormonal coils – a T-shaped plastic frame that is inserted into the uterus. It releases a type of the hormone progesterone. This thickens mucus around the cervix to stop sperm from reaching and fertilising an egg, thins the lining of the uterus, and prevents ovulation

Patient reviews