Contraceptive Pill Side Effects

Dr Clair Grainger

Medically reviewed by

Dr Clair Grainger

Last reviewed: 07 Oct 2019

What can change when you start taking the pill?

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

The contraceptive pill is one of the most common forms of contraception among women today. It can be up to 99% effective in preventing pregnancy when used correctly. But, as with most forms of hormonal contraceptive, there are also some possible side effects, it’s good to be aware of.

The two types of contraceptive pills are the combined contraceptive pill and the mini pill. They contain lab-made forms of two hormones that your body naturally produces. The combined pill is made up of oestrogen and progestogen, while the mini pill contains only progestogen.

Women generally react differently to hormones, so the side effects one woman may have when using the contraceptive pill will not be the same as another. Side effects of being on the pill can be positive as well as negative.

Order your contraceptive pill prescription online
Start Consultation

What are the most common side effects of the contraceptive pill?

Irregular bleeding

Both types of contraceptive pill work mainly by stopping ovulation (the monthly release of an egg from your ovaries). When you take the pill, you do not have periods but will likely experience some bleeding.

You will usually bleed with the combined pill during your pill-free week, but bleeding can be more unpredictable on the mini pill (taken continuously without a break).

It’s common to experience ‘breakthrough bleeding’ (unexpected bleeding or spotting) when using the pill, especially with the mini pill. This usually happens in the first three months of taking a particular type of pill and should get better after that.

If you start to have heavy bleeding or bleeding that lasts for more than a week, you should contact your doctor who may suggest you change to a different pill or form of contraception.

If you have unexpected or problematic bleeding that lasts more than 3 months after starting the pill, talk to your doctor to make sure there are no other underlying causes for this.

Feeling sick (nausea)

Feeling sick is more common within the first two to three months of using the contraceptive pill, and often goes away. It can help to take the pill with food, and preferably in the evening before bed. If you keep feeling sick, a pill with a lower amount of oestrogen may help.

Short-term weight gain

Some women may worry about weight gain when starting the contraceptive pill. There’s no proven link between taking the pill and long-term weight gain, though oestrogen and progesterone hormones can cause water retention and bloating.

You can manage any weight changes while on the pill by avoiding salty foods to help reduce water retention in your body. You can also restrict your food intake and exercise regularly to maintain a healthy weight.

Breast tenderness or swelling

The hormones in the contraceptive pill can cause changes in breast tissue which may cause pain and swelling. This should improve after the first few months of using the pill, as your body adjusts.

If you notice any lumps or abnormal swelling at any point or have breast pain lasting more than three months, you should contact your GP.


Women using the mini pill may notice spots or acne on their skin during the first few months. If it becomes distressing, contact your doctor to discuss other contraceptive options.

On the other hand, the combined contraceptive pill can help to clear acne, usually within a few months.

What are less common side effects of the contraceptive pill?

Mood changes

Some studies have suggested a link between using the combined pill and having mood changes or feeling depressed. This is likely to be caused by the hormone changes in your body after using the pill. It can be helped by changing the type of progesterone in your combined pill. Although mood changes are listed as a potential side effect of the mini pill by manufacturers, this has not been backed up in further studies.

If you notice frequent changes in your mood or any symptoms of feeling depressed, you should talk to your GP.


Although it’s a less common side effect, the hormones in contraceptive pills can increase your chances of getting mild headaches, or migraines, within the first few months of using the pill.

If you have migraines already, your GP may discuss using progesterone-only or non-hormonal methods of contraception, as the combined pill increases the risk of stroke in certain patients with migraine.

If you develop migraines after starting the combined pill, you should stop the pill, use condoms, and see your GP about alternative contraception.

You can manage mild headaches by drinking plenty of water, avoiding stress where possible, and taking the pill at the same time every day. If you still experience mild headaches after a few months, contact your GP about changing to a different pill or another type of contraception.

Reduced sex drive

Loss of sex drive is an uncommon side effect of the contraceptive pill. It is more common if you’re taking the mini pill. If you continue to experience less interest in having sex after a few months of using the pill, you should visit your GP who may suggest you change pills, or to a non-hormonal contraceptive method. They may also chat to you about any other possible reasons for your lower sex drive.

Are there any other risks of taking the contraceptive pill?

Apart from side effects, there are some other risks of being on the pill you should consider. A doctor can help you decide if these things may affect you, and whether the benefits of using the pill might outweigh the risks.

  • Using the combined pill has been linked with a small increased risk of breast cancer and cervical cancer. It is unclear if there is a link between the mini pill and breast cancer.
  • Oestrogen in the combined pill can increase your risk of developing blood clots, which can cause thrombosis (blood clots in your leg), stroke, or heart attack
  • The combined pill can also raise blood pressure in some women, especially if they have other risk factors for this like smoking, diabetes or being overweight

Taking the contraceptive pill with other medications

Some medicines can make the contraceptive pill less effective in preventing pregnancy. It is important to tell your doctor about all short- and long-term medicines you are currently taking, so you can both decide if the contraceptive pill is right for you. These medications include:

  • antibiotics like rifampicin and rifabutin used to treat tuberculosis (TB)
  • HIV medication
  • epilepsy medicines like carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone and topiramate
  • herbal medicines like St John’s wort
  • laxatives and weight-loss medications (these may affect the absorption of your pill in some cases)
  • acne medication (Roaccutane)

The contraceptive pill can also make some medicines you’re taking less effective, like epilepsy medications. Always check the patient information label and chat with your doctor or pharmacist for further advice.

How to find the right contraceptive pill for you

A doctor can advise you on the best contraceptive pill to use. They will ask you about your medical history and current lifestyle and advise which contraception is safest. Apart from potential side effects, you’ll also need to think about other factors, some of which include:

  • Age If you are over 35 and smoke, a doctor may suggest you try the mini pill, or other birth-control options because there is a higher risk of developing blood clots when taking contraception containing oestrogen
  • Being overweight If you’re overweight a doctor may advise against taking pills containing oestrogen as this increases your risk of blood clots and high blood pressure
  • Taking medications If you take long-term drugs for conditions like HIV or epilepsy they can reduce the effectiveness of contraceptive pills
  • Medical conditions The contraceptive pill may not be suitable if you have a history of illnesses like diabetes, high blood pressure, liver disease, breast cancer, blood clots, migraines, heart disease, or have recently given birth
  • Family history If you have a close relative who has suffered from blood clots at a young age you may be offered contraception which does not contain oestrogen

The best contraceptive pill for you may well be a balance of benefits, side effects, and risks. Some people find this combination with the first pill they take. For others, there can be some ‘trial and error’ before finding something that feels right.

The Lowdown is a good place to read about other women’s experiences with different pills.

Alternatives to the contraceptive pill

If you or your doctor think the pill might not be right for you, there are other effective contraceptive options you can consider.

Hormonal contraceptives

The contraceptive patch and the contraceptive vaginal ring have similar side effects to the combined pill and the same risks, including a higher risk of blood clots.

The progesterone-only contraceptive injection's common side effects include headaches, irregular periods, weight gain, and abdominal discomfort.

The progesterone-only contraceptive implant’s very common side effects can include irregular periods, acne, breast tenderness and headaches.

The IUS (intrauterine system) can cause irregular, heavier, or missed periods initially. Very common side effects include breast tenderness, acne and headaches.

The IUD (intrauterine device; copper coil)

Some women have reported heavy periods when using the IUD. There is also a risk of infection during the first three weeks of having the device put in place.

Barrier methods

Condoms are typically made of latex rubber which some people are allergic to. If this is the case, you can also get condoms made of non-latex materials. Condoms are typically less effective at preventing pregnancy than hormonal or long-acting contraception.

You could also use a contraceptive diaphragm which is made from silicone.

Order your contraceptive pill prescription online
Start Consultation
Medically reviewed by:
Dr Clair Grainger

Dr Clair Grainger studied at The University of Edinburgh from 2004 to 2009. She's worked in hospitals throughout Edinburgh and London before completing her GP training in North Middlesex Hospital in 2017.

Meet our doctors

Last reviewed: 07 Oct 2019

Order your contraceptive pill prescription online
Start Consultation

Contraceptive pills are a reliable way of reducing your risk of getting pregnant from sex. ZAVA offers most common brands of pill, so you can order your preferred brand by visiting our contraceptive pill service page.

trustpilot-ratings-4-star (2501)
trustpilot-ratings-5-star by Neil Sinclair, 07 Nov 2021
All worked well
trustpilot-ratings-5-star by Maria McCann, 18 Nov 2021
Efficient and easy ordering, with confidence it is being checked and approved by a Dr. Very fast delivery.
trustpilot-ratings-5-star by Patricia Naxton, 06 Nov 2021
I found ZAVA UK when searching via Boots the Chemists website for suppliers of the new Government-approved post-travel Lateral Flow tests. I needed to show proof of having ordered some before I could check in for our forthcoming holiday. I chose ZAVA as it was showing it to be "Trusted" amongst many other suppliers. I ordered the tests which were among the least expensive available and they arrived in the post the following day. I cannot fault the service.
trustpilot-ratings-5-star by Lorraine B, 26 Nov 2021
Very easy to navigate and tablets received early. Good service
trustpilot-ratings-5-star by Leanne, 18 Nov 2021
Always have a great experience with Zava med. postage always really quick which is important when ordering as I only remember at the last minute! Thank you!

Authorised and regulated by