Hormonal contraception

The pill, or combined pill, is a course of tablets containing two hormones, oestrogen and progestogen. To prevent pregnancy, the hormones:

• stop eggs being released from your ovaries each month - this is the main way they work
• thicken the mucus in your cervix (neck of the womb) - this makes it hard for sperm to move through it and reach an egg
• make the lining of your uterus (womb) thinner so it’s less likely to accept a fertilised egg.

The pill works on a 28-day cycle. With the most common type, you take the pill every day, at the same time, for 21 days, and then have a 7-day break.

The progestogen-only pill, POP, or the 'mini pill', is a daily tablet containing the hormone progestogen.

To prevent pregnancy, the mini pill:

• thickens the mucus in your cervix (neck of the womb) - this makes it hard for sperm to move through it and reach an egg
• makes the lining of your uterus (womb) thinner so it’s less likely to accept a fertilised egg.

Newer versions also stop eggs being released.

You take the pill at the same time every day. You don’t take a break as with the combined pill.

The contraceptive patch is a small, thin sticky patch that that contains two hormones, oestrogen and progestogen. You it put on your skin and both hormones are released into your bloodstream.

It prevents pregnancy in the same way as the combined pill.

In the UK, the brand name is Evra.

The patch also works on a 28-day cycle. You apply a new patch every 7 days for 21 days, and then have a 7- day patch-free break. At the end of the 7-day break, you apply a new patch and start a new cycle.

The vaginal ring is a flexible, transparent plastic ring that contains two hormones, oestrogen and progestogen.

It prevents pregnancy in the same way as the combined pill.

In the UK, it has the brand name NuvaRing.

The ring works on a 28-day cycle. You place it inside your vagina where it releases hormones into your body continually.

You wear it for 21 days, take it out and have a 7-day break. After the 7-day break, you put in a new ring and start a new cycle.

If you use hormonal contraception correctly all the time, it will be more than 99% effective at preventing pregnancy. Fewer than 1 in 100 women who use hormonal contraception properly will get pregnant.

• It does not interrupt sex.
• You'll likely have lighter periods, reduced period pain and less premenstrual symptoms. Some types of pill can help reduce acne too.
• It may provide some protection against ovarian, womb and colon cancer, according to research findings.

There can be some temporary side effects, such as:

• breast tenderness
• light bleeding
• mood changes.

There can also be some more serious side effects, such as:

• blood becoming stickier
• a slight increase in the risk of blood clots
• a slight increase in the risk of breast and cervical cancer.

Some of these risks may be greater, depending on your family medical history.

Most importantly, hormonal contraception does not provide any protection against HIV or other sexually transmitted infections like a condom does.

Hormonal contraception is not suitable for everyone.

The doctor or nurse prescribing it to you needs to know:

1. your medical history
2. your family’s medical history
3. about any other medication you’re taking.

Hormones are less likely to be prescribed if you:

• have high blood pressure
• are older than 35
• smoke
• suffer from migraines
• are very overweight.

Taking other medicines, such as antibiotics and anti-epileptic medicines, can make the hormonal pills less effective.

And if you have diarrhoea or vomiting, the pill might not work, and you will need to use an additional method of contraception, such as condoms.

Most importantly, hormonal contraception does not provide any protection against HIV or other sexually transmitted infections like a condom does.

All hormonal contraception is free on the NHS with a prescription from:

• GP or practice nurse at your GP surgery
• young person's clinic or community contraception clinic
• sexual health clinic or genitourinary medicine (GUM) clinic.

The progestogen-only pill (the mini pill) is available to buy at pharmacies without a prescription.