Long-acting reversible contraception (LARC)

The IUD (intra-uterine device) is a small T-shaped plastic and copper device that is placed in your uterus (womb) to prevent pregnancy. It is fitted by a specially trained doctor or nurse.

IUDs can be used by women of all ages, including childless women and those under 16.

Once fitted, an IUD can be left in place for 5 to 10 years, depending on the type.

How effective is it?

The IUD is over 99% effective in preventing pregnancy.

How does it work?

The IUD makes your uterus a very hostile environment for sperm and eggs.

It prevents pregnancy in 2 ways:

1. It releases copper into the uterus (womb), which makes it more difficult for sperm to reach an egg and survive. The copper won’t hurt you in any way.
2. T-shape physically stops fertilised eggs from implanting in your uterus and developing into a foetus.

Advantages of the IUD:

• it does not interrupt sex
• can be fitted at any time as long as you are not already pregnant
• there’s no need to remember to take anything
• available from different providers, including genitourinary medicine (GUM) and other sexual health clinics, GPs and abortion services
• your fertility or hormonal balance are not affected
• may be used as emergency contraception if fitted within 5 days of having unprotected sex.

Disadvantages of the IUD:

• it takes two appointments to have an IUD fitted: one for the initial chat and check up, and one for the actual fitting of the IUD
• fitting can be uncomfortable or painful, however local anaesthetic is usually used
• small risk of getting an infection after it’s been fitted
• if you have a sexually transmitted infection (STI) when the IUD is fitted or when it is in place it could lead to a pelvic infection if not treated; an IUD doesn’t increase your risk of infection
• may cause slightly longer and heavier periods, and some women also find their periods become a little more painful; however, many women notice very little difference at all
• very rarely, having the IUD fitted may perforate (make a small hole in) the uterus - this is unlikely if the doctor or nurse fitting your IUD has lots of experience.

The IUS (intra-uterine system) is similar to the IUD – it’s a small T-shaped plastic device which is fitted in the uterus by a specially trained doctor or nurse. It contains the hormone progestogen. It is often called the Mirena coil.

The IUS is a long-term contraceptive which can be left in place for between 5 to 7 years depending on when it was fitted.

How does it work?

The progestogen released by the IUS works in several ways to prevent pregnancy. It:

• 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
• may sometimes stop eggs being released from your ovaries (ovulation)
• T-shape physically stops fertilised eggs from implanting in your uterus and developing into a foetus.

How effective is it?

The IUS is over 99% effective at preventing pregnancy.

Advantages of the IUS:

• it does not interrupt sex
• can be fitted at any time as long as you're not already pregnant
• there’s no need to remember to take anything
• it’s available at a range of sites, including GUM and other sexual health clinics, GPs and abortion services
• can cause periods to be shorter and lighter, and for some women they may stop completely.

Disadvantages of the IUS:

• it usually takes two appointments to get an IUS: one for the initial chat and check up, and one for the actual fitting of the IUS
• fitting can be uncomfortable or painful, however local anaesthetic is usually used
• if you have a sexually transmitted infection (STI) when the IUD is fitted it could lead to a pelvic infection if not treated
• needs to be fitted by a specially trained doctor or nurse
• irregular periods, which some women find annoying or worrying; however, for most women this settles within the first 6 to 12 months after fitting
• there’s a small chance of developing an infection after having the IUS fitted; very rarely, having the IUS fitted may perforate (make a small hole in) the uterus - this is not likely if the doctor or nurse fitting the IUS has lots of experience.

Possible side effects:

• breast tenderness
• spotty skin
• headaches.

The contraceptive injection (the Depo or Depo-Provera or Sayana Press) is a long-acting contraception method containing the hormone progestogen.

It lasts for 8 to 13 weeks (depending on which injection you have). The hormone is injected into a muscle, usually the bottom.

You may be able to self-inject Sayana Press at home once you have been trained by your doctor or nurse.

How does it work?

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

How effective is it?

The contraceptive injection is over 99% effective in preventing pregnancy.

Advantages of the contraceptive injection:

• it does not interrupt sex
• lighter or no periods
• reduced period pain and less premenstrual symptoms
• research also suggests that it provides some protection against womb cancer and pelvic inflammatory disease.

Disadvantages of the contraceptive injection:

• It can disrupt periods, cause irregular bleeding, and for some women cause periods to be heavier and longer.
• Once you stop the injections it may take up to a year for your fertility to return to normal.
• Injections are not reversible, so if you have side effects, you will not be able to stop them until the injection has worn off after 8 to 13 weeks.
• It may cause thinning of the bones. This isn’t a problem for most women because the bone replaces itself when you stop the injection. You will be advised about the risks of osteoporosis (a disease that makes bones weak and fragile) before you’re prescribed the medication.
• It's not usually suitable for people aged under 18 because their bones are still being made.

Possible side effects:

• breast tenderness
• spotty skin
• headaches
• mood changes
• small weight gain.

The implant is a match-sized bendy stick which is placed just under the skin in your upper arm. It releases the hormone progestogen into your bloodstream.

It works for up to 3 years. It is also suitable if you want to get pregnant in the near future, as you become fertile again as soon as it is removed.

It has to be fitted by a specially trained doctor or nurse, so it may not be available at all GP surgeries or clinics.

How does the implant work?

• stops eggs being released from your ovaries each month.
• 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.

How effective is it?

The contraceptive implant is over 99% effective in preventing pregnancy.

Advantages of using the contraceptive implant

• it does not interrupt sex
• there’s no need to remember to take anything
• lighter or no periods, with reduced period pain and less premenstrual symptoms
• research suggests that it provides some protection against womb cancer and pelvic inflammatory disease.

It is generally safe for women who:

• are overweight
• smoke
• have a family history of heart disease.

Disadvantages of the hormonal implant

• it can disrupt periods, cause irregular bleeding, or cause periods to be heavier and longer
• some women will experience discomfort when the implant is put in and taken out, though local anaesthetic is usually used
• the skin where the implant is fitted can become infected, though this is rare.

Possible side effects:

• breast tenderness
• spotty skin
• headaches
• mood changes
• small weight gain.

LARC methods do not provide any protection against HIV or other sexually transmitted infections like a condom does.

The IUD, the IUS, the contraceptive injection and the hormonal implant are all available for free on the NHS. You can only get them on prescription and cannot buy them yourself at a pharmacy.

The IUD and the IUS can be obtained from a GP, a sexual health clinic, a practice nurse or a young person's clinic.