Introduction

Contraceptive implants and injections
Contraceptive implants and injections

A woman can get pregnant if a man’s sperm reaches one of her eggs (ova). Contraception tries to stop this happening by keeping the egg and sperm apart or by stopping egg production. Two newer methods of contraception are the contraceptive injection and contraceptive implants.

Contraceptive implant

The contraceptive implant is a small flexible tube about 40mm long that's inserted under the skin of your upper arm. It's inserted by a trained professional, such as a doctor, and lasts for three years. 

The implant stops the release of an egg from the ovary by slowly releasing progestogen into your body. Progestogen also thickens the cervical mucus and thins the womb lining. This makes it harder for sperm to move through your cervix, and less likely for your womb to accept a fertilised egg.

At a glance: the implant

  • If implanted correctly, it's more than 99% effective. Fewer than one woman in 1,000 who have the implant as contraception for three years will get pregnant.
  • It's very useful for women who know they don't want to get pregnant for a while. Once the implant is in place, you don't have to think about contraception for three years. 
  • It can be useful for women who can't use contraception that contains oestrogen. 
  • It's very useful for women who find it difficult to take a pill at the same time every day. 
  • If you have side effects, the implant can be taken out. You can have the implant removed at any time, and your natural fertility will return very quickly.
  • When it's first put in, you may feel some bruising, tenderness or swelling around the implant. 
  • In the first year after the implant is fitted, your periods may become irregular, lighter, heavier or longer. This usually settles down after the first year. 
  • A common side effect of the implant is that your periods stop (amenorrhoea). It's not harmful, but you may want to consider this before deciding to have an implant. 
  • Some medications can make the implant less effective, and additional contraceptive precautions need to be followed when you are taking these medications (see Will other medicines affect the implant?).
  • The implant does not protect against sexually transmitted infections (STIs). By using condoms as well as the implant, you'll help to protect yourself against STIs.

How the implant works

The implant steadily releases the hormone progestogen into your bloodstream. Progestogen is similar to the natural hormone progesterone, which is released by a woman's ovaries during her period.

The continuous release of progestogen:

  • stops a woman releasing an egg every month (ovulation) 
  • thickens the mucus from the cervix (entrance to the womb), making it difficult for sperm to pass through to the womb and reach an unfertilised egg
  • makes the lining of the womb thinner so that it is unable to support a fertilised egg

You can get contraception at:

  • most GP surgeries
  • community contraception clinics
  • some GUM clinics
  • sexual health clinics
  • some young people's services

Find a clinic near you

The implant can be put in at any time during your menstrual cycle, as long as you and your doctor are reasonably sure you are not pregnant. In the UK, Nexplanon is the main contraceptive implant currently in use. Implants inserted before October 2010 were called Implanon. Since October 2010, insertion of Implanon has decreased as stocks are used up, and Nexplanon has become the most commonly used implant.

Both types of implant work in the same way, but Nexplanon is designed to reduce the risk of insertion errors and is visible on an X-ray or CT (computerised tomography) scan. There is no need for existing Implanon users to have their implant removed and replaced by Nexplanon ahead of its usual replacement time.

Nexplanon is a small, thin, flexible tube about 4cm long. It is implanted under the skin of your upper arm by a doctor or nurse. A local anaesthetic is used to numb the area. The small wound made in your arm is closed with a dressing and does not need stitches.

Nexplanon works for up to three years before it needs to be replaced. You can continue to use it until you reach the menopause, when a woman’s monthly periods stop (at around 52 years of age). The implant can be removed at any time by a specially trained doctor or nurse. It only takes a few minutes to remove, using a local anaesthetic.

As soon as the implant has been removed, you will no longer be protected against pregnancy.

When it starts to work

If the implant is fitted during the first five days of your menstrual cycle, you will be immediately protected against becoming pregnant. If it is fitted on any other day of your menstrual cycle, you will not be protected against pregnancy for up to seven days, and should use another method, such as condoms.  

After giving birth

You can have the contraceptive implant fitted after you have given birth, usually after three weeks.

  • If it is fitted on or before day 21 after the birth, you will be immediately protected against becoming pregnant. 
  • If it is fitted after day 21, you will need to use additional contraception, such as condoms, for the following seven days.

It is safe to use the implant while you are breastfeeding.

After a miscarriage or abortion

The implant can be fitted immediately after a miscarriage or an abortion, and you will be protected against pregnancy straight away.

Who can use the implant

Most women can be fitted with the contraceptive implant. It may not be suitable if you:

Advantages and disadvantages of the implant

The main advantages of the contraceptive implant are:

  • it works for three years
  • the implant does not interrupt sex
  • it is an option if you cannot use oestrogen-based contraception, such as the combined contraceptive pill, contraceptive patch or vaginal ring
  • you do not have to remember to take a pill every day
  • the implant is safe to use while you are breastfeeding
  • your fertility should return to normal as soon as the implant is removed
  • implants offer some protection against pelvic inflammatory disease (the mucus from the cervix may stop bacteria entering the womb) and may also give some protection against cancer of the womb
  • the implant may reduce heavy periods or painful periods after the first year of use
  • after the contraceptive implant has been inserted, you should be able to carry out normal activities

Using a contraceptive implant may have some disadvantages, which you should consider carefully before deciding on the right method of contraception for you. These include:

Disrupted periods

Your periods may change significantly while using a contraceptive implant. Around 20% of women using the implant will have no bleeding, and almost 50% will have infrequent or prolonged bleeding. Bleeding patterns are likely to remain irregular, although they may settle down after the first year.

Although these changes are not harmful, they may not be acceptable for some women. Your GP may be able to help by providing additional medication if you have prolonged bleeding.

Other side effects that some women report are:

  • headaches
  • acne
  • nausea
  • breast tenderness
  • changes in mood
  • loss of sex drive

These side effects usually stop after the first few months. If you have prolonged or severe headaches or other side effects, tell your doctor.

Some women put on weight while using the implant, but there is no evidence to show that the implant causes weight gain.

Will other medicines affect the implant?

Some medicines can reduce the implant's effectiveness. These include:

  • medication for HIV
  • medication for epilepsy
  • complementary remedies, such as St John's Wort
  • an antibiotic called rifabutin (which can be used to treat tuberculosis)
  • an antibiotic called rifampicin (which can be used to treat several conditions, including tuberculosis and meningitis)

These are called enzyme-inducing drugs. If you are using these medicines for a short while (for example, rifampicin to protect against meningitis), it is recommended that you use additional contraception during the course of treatment and for 28 days afterwards. The additional contraception could be condoms, or a single dose of the contraceptive injection. The implant can remain in place if you have the injection.

Women taking enzyme-inducing drugs in the long term may wish to consider using a method of contraception that isn't affected by their medication.

Always tell your doctor that you are using an implant if you are prescribed any medicines. Ask your doctor or nurse for more details about the implant and other medication.

Risks of the implant

In rare cases, the area of skin where the implant has been fitted can become infected. If this happens, the area will be cleaned and may be treated with antibiotics.

Where you can get the contraceptive implant

Most types of contraception are available for free in the UK. Contraception is free to all women and men through the NHS. Places where you can get contraception include:

  • most GP surgeries – talk to your GP or practice nurse
  • community contraception clinics
  • some genitourinary medicine (GUM) clinics
  • sexual health clinics – they also offer contraceptive and STI testing services
  • some young people’s services (call 0300 123 7123 for more information)

Find your nearest sexual health clinic by searching by postcode or town.

Contraception services are free and confidential, including for people under the age of 16.

If you're under 16 and want contraception, the doctor, nurse or pharmacist won't tell your parents (or carer) as long as they believe you fully understand the information you're given, and your decisions. Doctors and nurses work under strict guidelines when dealing with people under 16. They'll encourage you to consider telling your parents, but they won't make you. The only time that a professional might want to tell someone else is if they believe you're at risk of harm, such as abuse. The risk would need to be serious, and they would usually discuss this with you first.

Contraceptive injection

There are three types of contraceptive injections in the UK: Depo-Provera, which lasts for 12 weeks, Sayana Press, which lasts for 13 weeks, and Noristerat, which lasts for eight weeks. The most popular is Depo-Provera. Noristerat is usually used for only short periods of time – for example, if your partner is waiting for a vasectomy.

The injection contains progestogen. This thickens the mucus in the cervix, stopping sperm reaching an egg. It also thins the womb lining and, in some, prevents the release of an egg.

At a glance: the contraceptive injection

  • If used correctly, the contraceptive injection is more than 99% effective. This means that less than one woman in 100 who use the injection will become pregnant in a year.
  • The injection lasts for eight, 12 or 13 weeks (depending on the type), so you don't have to think about contraception every day or every time you have sex.
  • It can be useful for women who might forget to take the contraceptive pill every day.
  • It can be useful for women who can't use contraception that contains oestrogen.
  • It's not affected by medication.
  • The contraceptive injection may provide some protection against cancer of the womb and pelvic inflammatory disease.
  • Side effects can include weight gain, headaches, mood swings, breast tenderness and irregular bleeding. The injection can't be removed from your body, so if you have side effects they'll last as long as the injection and for some time afterwards.
  • Your periods may become more irregular or longer, or stop altogether (amenorrhoea). Treatment is available if your bleeding is heavy or longer than normal – talk to your doctor or nurse about this.
  • It can take up to one year for your fertility to return to normal after the injection wears off, so it may not be suitable if you want to have a baby in the near future.
  • Using Depo-Provera affects your natural oestrogen levels, which can cause thinning of the bones. 
  • The injection does not protect against sexually transmitted infections (STIs). By using condoms as well as the injection, you'll help to protect yourself against STIs.

How the injection works

You can get contraception at:

  • most GP surgeries
  • community contraception clinics
  • some GUM clinics
  • sexual health clinics
  • some young people's services

Find a clinic near you

The contraceptive injections Depo-Provera and Noristerat are usually given into a muscle in your bottom, although sometimes may be given in a muscle in your upper arm. Sayana Press is given under the skin (subcutaneously) rather than into a muscle, in the abdomen or thigh.

The contraceptive injection works in the same way as the implant. It steadily releases the hormone progestogen into your bloodstream. Progestogen is similar to the natural hormone progesterone, which is released by a woman's ovaries during her period.

The continuous release of progestogen:

  • stops a woman releasing an egg every month (ovulation) 
  • thickens the mucus from the cervix (neck of the womb), making it difficult for sperm to pass through to the womb and reach an unfertilised egg 
  • makes the lining of the womb thinner, so that it is unable to support a fertilised egg

The injection can be given at any time during your menstrual cycle, as long as you and your doctor are reasonably sure you are not pregnant.

When it starts to work

If you have the injection during the first five days of your cycle, you will be immediately protected against becoming pregnant. 

If you have the injection on any other day of your cycle, you will not be protected against pregnancy for up to seven days. Use condoms or another method of contraception during this time.

After giving birth

You can have the contraceptive injection at any time after you have given birth, if you are not breastfeeding. If you are breastfeeding, the injection will usually be given after six weeks, although it may be given earlier if necessary.

  • If you start injections on or before day 21 after giving birth, you will be immediately protected against becoming pregnant.
  • If you start injections after day 21, you will need to use additional contraception for the following seven days.

Heavy and irregular bleeding is more likely to occur if you have the contraceptive injection during the first few weeks after giving birth.

It is safe to use contraceptive injections while you are breastfeeding.

After a miscarriage or abortion

You can have the injection immediately after a miscarriage or abortion, and you will be protected against pregnancy straight away. If you have the injection more than five days after a miscarriage or abortion, you'll need to use additional contraception for seven days.

Who can use the injection?

Most women can be given the contraceptive injection. It may not be suitable if you:

Advantages and disadvantages of the injection

The main advantages of the contraceptive injection are:

  • each injection lasts for either eight, 12 or 13 weeks 
  • the injection does not interrupt sex 
  • the injection is an option if you cannot use oestrogen-based contraception, such as the combined pill, contraceptive patch or vaginal ring
  • you do not have to remember to take a pill every day
  • the injection is safe to use while you are breastfeeding 
  • the injection is not affected by other medicines
  • the injection may reduce heavy, painful periods and help with premenstrual symptoms for some women
  • the injection offers some protection from pelvic inflammatory disease (the mucus from the cervix may stop bacteria entering the womb) and may also give some protection against cancer of the womb

Using the contraceptive injection may have some disadvantages, which you should consider carefully before deciding on the right method of contraception for you. These are as follows:

Disrupted periods

Your periods may change significantly during the first year of using the injection. They will usually become irregular and may be very heavy, or shorter and lighter, or stop altogether. This may settle down after the first year, but may continue as long as the injected progestogen remains in your body.

It can take a while for your periods and natural fertility to return after you stop using the injection. It takes around eight to 12 weeks for injected progestogen to leave the body, but you may have to wait longer for your periods to return to normal if you are trying to get pregnant.

Until you are ovulating regularly each month, it can be difficult to work out when you are at your most fertile. In some cases, it can take three months to a year for your periods to return to normal.

Weight gain

You may put on weight when you use the contraceptive injection, particulaly if you are under 18 years old and are overweight with a BMI (body mass index) of 30 or over.   

Other side effects that some women report are:

  • headaches
  • acne
  • tender breasts
  • changes in mood
  • loss of sex drive

Depo-Provera, oestrogen and bone risk

Using Depo-Provera affects your natural oestrogen levels, which can cause thinning of the bones, but it does not increase your risk of breaking a bone. This isn't a problem for most women, because the bone replaces itself when you stop the injection, and it doesn't appear to cause any long-term problems.

Thinning of the bones may be a problem for women who already have an increased risk of developing osteoporosis (for example, because they have low oestrogen, or a family history of osteoporosis). It may also be a concern for women under 18, because the body is still making bone at this age. Women under 18 may use Depo-Provera, but only after careful evaluation by a doctor.

Will other medicines affect the injection?

No – the contraceptive injection is not affected by other medication.

Risks

There is a small risk of infection at the site of the injection. In very rare cases, some people may have an allergic reaction to the injection.

Where you can get it

Most types of contraception are available free in the UK. Contraception is free to all women and men through the NHS. You can get contraception at:

  • most GP surgeries – talk to your GP or practice nurse
  • community contraception clinics
  • some genitourinary medicine (GUM) clinics 
  • sexual health clinics – they also offer contraceptive and STI testing services
  • some young people’s services (call 0300 123 7123 for more information)

Find your nearest sexual health clinic by searching your postcode or town.

Contraception services are free and confidential, including for people under the age of 16.

If you're under 16 and want contraception, the doctor, nurse or pharmacist won't tell your parents (or carer) as long as they believe you fully understand the information you're given, and your decisions. Doctors and nurses work under strict guidelines when dealing with people under 16.

They'll encourage you to consider telling your parents, but they won't make you. The only time that a professional might want to tell someone else is if they believe you're at risk of harm, such as abuse. The risk would need to be serious, and they would usually discuss this with you first.

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 03/05/2016 08:59:06