Women’s health centre

The combined contraceptive pill can cause some side effects. Possible problems include feeling sick, getting headaches, changes in your weight, breast tenderness, or an increase in the size of your breasts.^[23]

Some women get high blood pressure, feel depressed, or find they have a lower sex drive.^[23]

The pill can also cause some more serious side effects. These may sound worrying, but the chance of getting a serious side effect is very small.

It's also worth remembering that the combined contraceptive pill can actually help protect against some kinds of cancer. You're less likely to get cancer of the ovaries or cancer of the womb lining (endometrial cancer) if you're taking the pill.^[23]

The pill can increase your risk of getting a blood clot inside one of your blood vessels. If a blood clot forms in a vein deep in your leg, it's called a deep vein thrombosis (a DVT). But the chance of this happening is fairly small.^[23]

• For women who don't take the pill, each year there's about a 5 in 100,000 chance of getting a DVT

• For women who do take the pill, the chance of getting a DVT is between 15 in 100,000 and 25 in 100,000, depending on the type of pill.

If a DVT travels through your bloodstream into your lungs, it can be very dangerous. But it's very rare for women to die of a DVT because of the pill. Over a year, the risk of dying of a DVT because of the pill is somewhere between 2 in a million and 10 in a million.^[24]

If you have a blood clot in a deep vein, you usually get pain, swelling, warmth, and redness in one of your legs. See a doctor straight away if you have any of these symptoms.

Taking the pill for more than five years slightly increases your risk of getting cervical cancer. However, your overall risk of getting cervical cancer is low, whether or not you take the pill.^[25]

• Out of 10,000 women who don't take the pill, doctors would expect to see 38 cases of cervical cancer by the age of 50.

• Out of 10,000 women who took the pill for five years from the age of 20, doctors would expect to see 40 cases of cervical cancer. So, that's two extra cases of cancer in 10,000 women taking the pill.

When you stop taking the pill, your risk of cervical cancer drops back to normal.^[25] About 10 years after you finish taking the pill, your chance of getting cervical cancer is the same as if you'd never taken it.