Contraceptive injection

Effectiveness

Over 99 per cent effective.
Less than one woman in 100 will get pregnant in a year.

How it works

Releases the hormone progestogen which stops ovulation,
thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus to prevent a fertilised egg implanting.

Advantages

Lasts for 12 weeks (Depo-Provera) or eight weeks (Noristerat).

May protect against cancer of the uterus, and offers some protection from pelvic inflammatory disease.

You don’t have to think about contraception for as long as the injection lasts.

Disadvantages

Periods may stop, be irregular or longer.

Periods and fertility may take time to return after stopping the injection.

Some women gain weight.

Some women report having headaches, acne, mood changes and breast tenderness.

Comments

The injection cannot be removed from the body so any side-effects may continue for as long as it works and for some time afterwards.

Not affected by other medicines.

Find out more about contraceptive injections.

Implant

Effectiveness

Over 99 per cent effective. Less than one woman in 1,000 will get pregnant over three years.

How it works

Small flexible rod put under the skin of the upper arm. Releases the hormone progestogen. It stops ovulation, thickens cervical mucus to prevent sperm reaching an egg, and thins the lining of the uterus to prevent a fertilised egg implanting.

Advantages

Works for three years but can be taken out sooner.

You don’t have to think about contraception for as long as the implant is in place.

When the implant is removed your fertility will return will return to normal.

Disadvantages

Periods may stop, be irregular or longer.

Acne may occur.

Some women report having mood changes and breast tenderness.

It requires a small procedure to fit and remove it.

Comments

Put in using a local anaesthetic and no stitches are needed.

Tenderness, bruising and some swelling may occur.

You may feel the implant with your fingers, but it can’t be seen.

Some medicines may stop the implant from working.

Find out more about the contraceptive implant.

Intrauterine system (IUS)

Effectiveness

Over 99 per cent effective.
Less than one woman in 100 will get pregnant over five years.

How it works

A small T-shaped plastic device which slowly releases the hormone progestogen is put into the uterus. This thickens cervical mucus to prevent sperm reaching an egg, thins the lining of the uterus to prevent a fertilised egg implanting and may stop ovulation.

Advantages

Works for five years but can be taken out sooner.

Periods usually become lighter, shorter and sometimes less painful.

You don’t have to think about contraception for as long as the IUS is in place.

When the IUS is removed your fertility will return to normal.

Disadvantages

Irregular bleeding or spotting is common in the first six months.

Periods may stop altogether. Some women report having acne, headaches and breast tenderness.

Very small chance of getting an infection during the first 20 days after insertion.

May get ovarian cysts.

Comments

If fitted after 45 it can stay in place until the menopause.

Women are taught to check the IUS is in place.

Can be useful for women with very heavy and/or painful periods.

A check for any existing infection is usually advised before an IUS is put in.

Not affected by other medicines.

Find out more about the IUS.

Intrauterine device (IUD)

Effectiveness

Over 99 per cent effective.
Less than one woman in 100 will get pregnant in a year, depending on the type of IUD. Older IUDs have less copper and are less effective.

How it works

A small plastic and copper device is put into the uterus. It stops sperm reaching an egg, and may also stop a fertilised egg implanting in the uterus.

Advantages

Works as soon as it is put in.

Can stay in 5–10 years depending on type, but can be taken out at any time.

You don’t have to think about contraception for as long as the IUD is in place.

When the IUD is removed your fertility will return to normal.

Disadvantages

May not be suitable for women at risk of getting a sexually transmitted infection.

Periods may be heavier or longer and more painful.

Very small chance of getting an infection during the first 20 days after insertion.

A small increased risk of ectopic pregnancy if the IUD fails.

Comments

If fitted after 40 it can stay in place until the menopause.

Women are taught to check the IUD is in place by feeling the threads high in their vagina.

A check for any existing infection is usually advised before an IUD is put in.

Not affected by other medicines.

Find out more about the IUD.

Female sterilisation

Effectiveness

The overall failure rate is about one in 200. This is a permanent method suitable for people who are sure they never want children or do not want more children.

How it works

The fallopian tubes are cut or blocked to prevent sperm reaching an egg. This stops the sperm and egg meeting.

Advantages

It does not interrupt sex.

Sterilisation is permanent with no long- or short-term serious side-effects.

Once the operation has worked you don't have to think about contraception.

Periods are unaffected.

Disadvantages

All operations carry some risk, but the risk of serious complications is low.

There is a small increased rick of ectopic pregnancy if female sterilisation fails.

A general anaesthetic is usually needed.

Comments

Should not be chosen if in any doubt, and counselling is important.

You may experience discomfort or some pain for a short time after sterilisation. It is important to rest and avoid strenuous activity for a while after the procedure.

Find out more about female and male sterilisation.

Back to Your guide to contraception.

Male sterilisation (vasectomy)

Effectiveness

About one in 2,000 male sterilisations fail. This is a permanent method suitable for people who are sure they never want children or do not want more children.

How it works

The tube (vas deferens) that carrier sperm from the testicles to the penis is cut, sealed or blocked to prevent sperm reaching an egg.

Advantages

It does not interrupt sex.

Sterilisation is permanent with no long- or short-term serious side-effects.

Once the operation has worked you don't have to think about contraception.

Usually performed under a local anaesthetic.

Disadvantages

Contraception must be used until a semen test shows that no sperm are left. This can take at least two months.

Some men can experience ongoing testicle pain. This is not common.

Comments

Should not be chosen if in any doubt, and counselling is important.

You may experience discomfort or some pain for a short time after sterilisation. It is important to rest and avoid strenuous activity for a while after the procedure.

Find out more about female and male sterilisation.

Back to Your guide to contraception