The combined pill

The combined pill is a tablet containing hormones that stop you getting pregnant. Find out how it works.

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 combined pill contains hormones oestrogen and progestogen. These are synthetic versions of the hormones that are naturally released from your ovaries. You take the pill every day for 21 days, then stop for seven days. During that week, you have a period-type bleed. After seven days, you start taking the pill again.

How does the combined pill work?

The hormones 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.

How effective is it?

If used correctly, the combined pill can be more than 99% effective. This means that fewer than one woman in 100 who takes the pill will get pregnant in one year. The chance of getting pregnant rises if:

you don't take the pill according to the instructions
it doesn't stay in the body long enough to work, for example, when you vomit
other medications make it less effective

Find out what to do if you're on the pill and you're sick or have diarrhoea.

Added benefits?

You don’t ovulate when you take the combined pill, so you don’t have a real period every month. Instead, you get a withdrawal bleed, which can be much lighter and shorter than a period. If you have problems with heavy periods or painful periods, taking the combined pill can help.

The pill can protect against cancer of the ovary, cancer of the womb, cancer of the colon and some pelvic infections.

What else should I know?

To be effective, the pill must be taken at the same time every day, and on the correct days – find out more about how to take the combined pill.
You could get pregnant if you don’t take the pill at the same time every day, you miss one, you vomit or have severe diarrhoea, or you take some other types of medication.
The combined pill isn’t suitable for women over 35 who smoke, or women with certain medical conditions. Your doctor or nurse can tell you whether you can take this kind of pill.
There's a very low risk of serious side effects, including blood clots (embolism) and cervical cancer, although the risk of blood clots when taking the pill is less than the natural risk of blood clots during pregnancy.
Minor side effects include mood swings, breast tenderness and headaches.
There's no evidence that the combined pill causes women to gain weight.

By using condoms as well as the combined pill, you'll help to protect yourself against sexually transmitted infections (STIs) such as chlamydia and gonorrhoea.