A contraceptive implant is a device that is put under the skin in order to offer you an even dose of contraception without you having to take a daily pill.
What is the contraceptive implant?
A contraceptive implant is a small, flexible rod about the size of a matchstick. The implant contains a progestogen hormone which provides contraception without you having to take a daily pill. The rod is put under the skin on your arm. The only contraceptive implant currently available in the UK is Nexplanon® (there are other devices available elsewhere in the world).
Nexplanon® is 40 mm long and 2 mm wide. That is, about the size of a normal matchstick.
How effective is the contraceptive implant?
The contraceptive implant is over 99% effective. Only around 1 in 3,000 sexually active women using the implant will become pregnant each year, often because they were actually pregnant at the time of insertion. This is the lowest contraceptive failure rate of any method, including sterilisation (male or female). In fact in most studies of the implant, no women became pregnant at all.
Compare this to when no contraception is used: around 4 out of 5 sexually active women become pregnant within one year.
How does the contraceptive implant work?
1 of 4 How does the implant work on the body?
The progestogen hormone in the implant is called etonogestrel. It is released into the bloodstream at a slow, steady rate.
The progestogen works mainly by stopping the release of the egg from the ovary. It also thickens the cervical mucus which forms a plug in the neck of the womb (cervix). This stops sperm getting through to the womb (uterus) to fertilise an egg.
It also makes the lining of the womb thinner. This means that if an egg were to fertilise, it would not be likely to be able to attach to the womb (implantation).
In order for you to get pregnant you need all of these things to be working (ovulation, sperm getting through the cervix, and implantation). The contraceptive implant blocks all three stages.
How quickly does the contraceptive implant work?
If an implant is put in during the first five days of your period, you are protected against pregnancy immediately.
If an implant is put in at any other time during your cycle, you are not protected until seven days have passed. You will need to use additional contraception if you wish to be sexually active during this time.
You should only have an implant put in if it is certain that you are not already pregnant.
Where can I get the contraceptive implant?
The contraceptive implant has to be fitted by a specially trained nurse or doctor. This service may be offered at your local GP surgery and, if it is, how to arrange it will probably be explained on their website. Alternatively, a contraception, sexual health or community gynaecology clinic will do this for you. You can find details of services in your area in the UK online.
In the UK the contraceptive implant is free of charge.
All contraceptive services are completely confidential. You will not need an internal examination, a breast examination or a smear before you can have a contraceptive implant. In some cases you may need a pregnancy test to be certain that you are not already pregnant.
How is the contraceptive implant put in?
The contraceptive implant is about the size of a matchstick and is placed under the skin of the inner side of your upper arm.
- An injection of local anaesthetic is used to numb the skin.
- A special device is used to place the implant under the skin. The wound is dressed and will soon heal just like any other small cut.
- The area around the implant may be bruised and tender for a few days.
- Once it has healed, knocking the implant will not do it, or you, any harm.
- You do not need to have an internal vaginal examination or a genital examination to have an implant.
How long do contraceptive implants last?
The contraceptive implant is fully effective for three years, but it stops being effective if it is removed. After three years, if you want to continue using this method of contraception, you will need a new implant.
How is the contraceptive implant taken out?
A trained doctor or nurse must take your implant out. They will give you a local anaesthetic injection in the area where the implant is. They will then make a tiny cut in your skin and gently pull the implant out.
By Vera de Kok (Own work), via Wikimedia Commons
They will put a dressing on the arm, which you should keep on for a few days.
Occasionally, an implant is difficult to feel under the skin, in which case you may be referred to a specialist centre to have it removed with the help of an ultrasound scan. If you want to carry on using an implant, the doctor or nurse can put a new one in at the same time. If you do this there will be no break in your contraceptive protection.
The implant can be taken out at any time if you request removal. It loses its effect immediately after being removed.
Do I need regular check-ups if I have an implant?
You don't need regular check-ups, so if all is well you do not need to see your doctor or nurse until you need the implant replaced, or you want it removed. However, you can return at any time to discuss any problems. You should see your doctor or nurse if any of the following occur:
- You cannot feel your implant.
- Your implant appears to have changed shape.
- You notice any change in your skin or have any pain in the area around the implant.
- You become pregnant.
- You develop irregular bleeding or bleeding after having sex (intercourse).
When should the implant be put in?
You can have an implant fitted at any time in your menstrual cycle if it is certain that you are not pregnant.
- If the implant is put in during the first five days of your period you will be protected against pregnancy immediately.
- After day 5 and if you haven't had unprotected sexual intercourse (UPSI) since your last period, the implant can be inserted immediately but you should avoid sexual intercourse or use a barrier method of contraception (such as condoms) for 7 days.
- If you have had unprotected sexual intercourse since your last period you may need a pregnancy test and emergency contraception. You should discuss this with your clinician.
If you have recently had a baby the implant can be put in at any time after the birth. If the implant is inserted on or before day 21, your contraceptive protection starts straightaway. (You can't become pregnant in the first 21 days after delivery, so as long as you have it inserted any time up to day 21 you are protected.) If it is fitted later than this and you have had unprotected sexual intercourse, you may need a pregnancy test and emergency contraception. You should discuss this with your clinician.
If you have had a termination of pregnancy or a miscarriage the implant can be put in at the same time, or in the first five days, and is effective immediately.
What are the side-effects with a contraceptive implant?
Most side-effects caused by the contraceptive implant occur when you first start using the implant. They are not usually severe.
The most common side-effects are:
- Changes in your periods (see below).
- Fluid retention and breast tenderness.
- Acne: your skin may temporarily worsen, although it can also improve.
- Itching or bruising after implant insertion.
The contraceptive implant does not cause 'thinning' of your bones (osteoporosis). It does not usually cause altered sex drive (libido), but some women who have experienced other side-effects also say that their sex drive was reduced.
Other symptoms, including mood swings or low mood, weight gain and breast tenderness, are commonly described. However, the evidence that they are caused by the contraceptive implant is very unclear, as they seem to occur equally commonly in women using non-hormonal methods of contraception.
Does the contraceptive implant stop periods?
Most women experience changes in their periods with a contraceptive implant.
- Most commonly, the periods will be lighter and less regular.
- Some women find that their periods stop altogether with the implant (amenorrhoea).
- A few women have longer, irregular periods, which can be heavy.
- Some women experience mood swings at first, which can be like pre-menstrual mood swings (PMS).
If you have prolonged bleeding with the contraceptive implant your doctor or nurse can prescribe extra hormone tablets to suppress the bleeding until it settles by itself. This way you keep the contraceptive cover, and the periods will usually settle down over time. This usually happens within three months of having the implant inserted.
Does the contraceptive implant cause weight gain?
There is no strong evidence that the contraceptive implant makes women put on weight. Progesterone can do this, but more so when taken in higher doses than you receive from the contraceptive implant. It can also cause fluid retention initially - which will make your weight go up - but this is usually due to fluid rather than fat.
However, many women do feel that the contraceptive implant has made them gain weight. If this happens to you then this weight gain is likely to reverse when you stop using the implant.
The early side-effects of the contraceptive implant are rather like the early symptoms of pregnancy. This is not surprising, since the early symptoms of pregnancy are caused by progesterone. It is not unusual for women to feel they may be pregnant when they first have the implant. A pregnancy test will give you an accurate answer.
Are there any risks from using the contraceptive implant?
Women who use some forms of hormone-based contraception appear to have a small increase in long-term risk of being diagnosed with breast cancer compared to women who don't use hormonal contraception. It is not known if this is also true of the contraceptive implant.
Apart from bruising and soreness, it is possible, although very unusual, to get a localised infection in your arm when the implant is put in. Insertion of the implant can leave a small scar.
It is important to be able to feel the implant under the skin after insertion. There is a small risk of insertion error in which the implant is not actually inserted by the procedure.
Can I have the implant after emergency contraception?
After taking levonorgestrel as emergency contraception the implant can be inserted immediately. You should avoid sex or use a barrier method of contraception (such as condoms) for 7 days. In addition you should take a pregnancy test 3 weeks or so after the time you had unprotected sex.
If you took ulipristal acetate the implant should be inserted 5 days after taking the tablet. You should avoid having unprotected sex or use a barrier method of contraception (such as condoms) until the implant is inserted and for 7 days after. You should also take a pregnancy test no sooner than 3 weeks after the last time you had unprotected sex.
Can a contraceptive implant be used when breastfeeding?
Yes, an implant can be used when breastfeeding. The implant will not affect your milk production and will not harm your baby.
Although breastfeeding does slightly reduce the chance of another pregnancy, it is not a reliable contraceptive and it is possible to become pregnant whilst breastfeeding.
Can anything make an implant less effective?
Some medicines may make an implant less effective. This includes some medicines used in epilepsy, HIV and tuberculosis, and St John's wort (a herbal remedy often used to treat headaches, mood disturbances and premenstrual syndrome). These medications reduce the effectiveness of the implant by increasing the rate at which your body disposes of the hormone in the blood. If you are using one of these medicines you will need to consider a different or additional contraceptive method.
The implant is not affected by common antibiotics, or by an attack of diarrhoea or being sick (vomiting).
Is there anyone who should not have a contraceptive implant?
Most women can have an implant fitted but there are a few exceptions. You should not have a contraceptive implant put in if you think you might be pregnant, or if you don't want to use a contraceptive method that might affect your periods.
You also should not use the contraceptive implant if:
- You are taking medicines which might interfere with the implant.
- You have heart or liver disease.
- You have had breast cancer in the previous five years.
- You are currently experiencing unexplained vaginal bleeding.
- You have a hereditary blood disorder called porphyria.
There are some conditions which, if you have them, mean that you could use the contraceptive implant, but a different method might be more suitable for you. These include:
- You are going to have major surgery with prolonged immobilisation.
- You have an increased risk of blood clots in the veins due to antiphospholipid syndrome, antithrombin deficiency or factor V Leiden.
- You have previously had a deep vein thrombosis or pulmonary embolism.
- You have migraines.
- You have systemic lupus erythematosus.
- You have gene mutations associated with breast cancer - for example, BRCA1.
- You have cervical cancer.
- You have experienced a stroke, angina or heart attack.
- You have several risk factors for heart disease, such as smoking, high cholesterol, high blood pressure, diabetes.
- You have had jaundice or itching caused by previous use of a hormonal contraceptive.
How do I change from another contraceptive method?
The contraceptive implant needs to have been in place for seven days before it can stop ovulation. Therefore, when you change from another method, precautions may be necessary for seven days. (This is sometimes not necessary, but only if your previous method means that there is no chance of you ovulating during the first seven days of the implant.)
How do I change to the implant from the combined pill?
If you are taking the regular, combined hormone contraceptive (CHC) pill, the implant can be inserted on the first or second pill-free day after you finish the packet. Protection is then continued without a break.
If you have the implant inserted during the remaining days of the pill-free interval you should use additional protection for the first seven days. If you have had unprotected sex (intercourse) during the gap, you are also advised to restart your CHC for at least seven days, taking it when you would normally have done so.
If you have the contraceptive implant inserted in the first seven days of your pill packet, you should either avoid sex, continue taking your CHC for a further seven days, or use an additional barrier method.
If you have the contraceptive implant inserted when you are more than seven days into your CHC pill packet, and have not missed any pills, you are covered immediately and do not need to finish your pill packet.
How do I change to the implant from an injectable contraceptive?
If you put the contraceptive implant in whilst your injection is still active (ie within 14 weeks of your last injection), you are covered immediately.
If you have 'gone over' the 14 weeks by a day or more, you can still have the contraceptive implant but need to use additional precautions for seven days. If you had unprotected intercourse in the interval, you should also take emergency contraception, and if you do not have a period, you should do a pregnancy test three weeks later.
How do I change to the implant from the progestogen-only pill?
If switching from the progestogen-only pill (POP), you should continue the POP for seven days after the implant has been inserted, or use other methods. If you were using a desogestrel pill, you are protected immediately and no additional precautions are required.
How do I change to the implant from the progestogen intrauterine system (such as Mirena® or Jaydess®)?
If switching from the intrauterine system (IUS), you should keep your IUS in place, or use other methods, for the first seven days after insertion of the implant.
How do I change to the implant from the intrauterine contraceptive device?
If switching to the contraceptive implant from the copper intrauterine contraceptive device (IUCD), you should leave your IUCD in place, or use another method, for the first seven days after insertion of the implant.
How do I change to the implant from a non-hormonal method?
If your implant is inserted on day 1-5 of your menstrual cycle, no other precautions are needed; you are covered straightaway.
If your implant is inserted at any other time, you need to be sure you are not pregnant, and to take extra precautions for the first seven days.
If I have a contraceptive implant, what do I do when I want to try to get pregnant?
If you want to try for a baby, you need to have the implant removed. Your periods will return to normal, although it can be up to three months before you get back to your old rhythm. However, it is possible to get pregnant before you have your first period.
Start pre-pregnancy care such as taking folic acid, stopping smoking and considering any regular medication you take beforehand. You can ask your doctor or nurse for further advice.
Dr Mary Lowth is an author or the original author of this leaflet.
Further reading and references
Contraception - progestogen-only methods; NICE CKS, March 2021 (UK access only)
Trussell J; Contraceptive failure in the United States, Contraception, 2011
UK Medical Eligibility Criteria Summary Table for intrauterine and hormonal contraception; Faculty of Sexual and Reproductive Healthcare, 2016 - amended September 2019