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How can I avoid pregnancy? - Your contraception guide

Knowing effective methods of contraception is the best way to avoid getting pregnant. It can also help to find out more about when you're likely to release an egg (ovulate). This can help you plan or avoid pregnancy.

Avoiding pregnancy

There are many methods of contraception you can choose from to avoid pregnancy. Condoms are the only method that helps protect against both pregnancy and sexually transmitted infections (STIs).

It's difficult to know exactly when ovulation happens. So if you're trying to avoid pregnancy, there isn't a "safe" time of the month to have unprotected sex.

For a woman with a shorter menstrual cycle (for example, 23 days), having unprotected sex during her period could put her at risk of pregnancy.

The most effective methods of contraception are long-acting reversible contraceptive methods, such as the contraceptive injection, contraceptive implant, intrauterine system and intrauterine device (IUD).

Emergency contraception

If you've had unprotected sex or your contraception has failed, emergency contraception can help prevent an unplanned pregnancy.

There are two types: the emergency contraceptive pill and the IUD.

The emergency contraceptive pill

There are two kinds of emergency contraceptive pill, also known as the "morning after pill".

Levonelle has to be taken within 72 hours (three days) of sex, and ellaOne has to be taken within 120 hours (five days) of sex.

But it's important to remember that the sooner you take emergency contraception after sex, the more effective it will be. Both work by preventing or delaying ovulation.


The IUD is a small, T-shaped contraceptive device made from plastic and copper. It's inserted into the uterus by a trained health professional.

It may prevent an egg implanting in your womb or being fertilised.

The IUD can be inserted up to five days after unprotected sex, or up to five days after the earliest time you could have ovulated.

If you have any questions, you can speak to a pharmacist or GP, or visit a sexual health or family planning clinic.

Find out more about emergency contraception, including where to get it.

When am I most likely to get pregnant?

During the menstrual cycle, an egg is released from one of your ovaries and travels down the fallopian tube.

The egg only lives for 24 hours after ovulation, and a sperm must meet the egg within that period for pregnancy to happen.

This doesn't mean that a woman has to have sex on the day of ovulation, as sperm can survive in your body for several days after sex.

If you want to get pregnant, having sex every couple of days will mean there are always sperm waiting to meet the egg when it's released.

Find out more about planning a pregnancy.

If you think you might be pregnant, read about the signs and symptoms of pregnancy and doing a pregnancy test.

When does ovulation happen?

It's difficult to pinpoint exactly when ovulation happens, but usually it takes place 10-16 days before the start of your next period.

The first day of your period is day one of your menstrual cycle. The average cycle takes 28 days, but shorter or longer cycles are normal.

Read more about periods and fertility.

Page last reviewed: 24 March 2021
Next review due: 24 March 2024