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Written by Dr David Delvin, GP and family planning specialist
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For quite a lot of women, the idea of having a contraceptive
implanted under the skin of your arm is quite attractive.
Why? Because of the fact, that once it’s been implanted, then
with luck you can more or less forget about it. You can make love whenever you
want to, without worrying about taking
Pills or buying
condoms!
Implants were first used on a wide scale back in the 1990s. They
received rather a bad press, partly because they so often caused menstrual
problems, and partly because some of them were put in by doctors who had no
real idea what they were doing; as a result, some women developed pain or
infection at the insertion site.
Even today, you should make absolutely sure that a doctor who
offers to give you a contraceptive implant has been fully trained in the
insertion technique. In Britain, only a small minority of medics have this
particular skill.
In the early 2000s, there were stories that implants could ‘move
around’ inside your body. These put some women off. We deal with this concern
below.
What does an implant actually do?
From its position under your skin, it releases a steady stream
of the female-type hormone etonorgestrol into your bloodstream. The hormone reaches your
ovaries, and prevents them from releasing eggs. It also causes some minor
anti-conception changes in your womb lining and in your cervix. Therefore, you
don’t get pregnant – or at least, the chances of pregnancy are very small
indeed.
The implant goes on working for several years (three years in
the case of Implanon (etonogestrel)), after which it runs out of hormone. If, at the end of
that time, you want to continue with the method, you would need to have the
device replaced.
And if at any time you get fed up with the implant – for
instance, because of side-effects (see below) – you can have it removed.
However, once again you should make sure that the doctor who does the removal
has been properly trained for the job. If you’re having trouble finding
someone, ring the nearest Family Planning Clinic for advice.
What are the long-term consequences of having hormones released
from an implant?
Frankly, we don’t know. Implants just haven’t been around long
enough for anybody to find out. Obviously, it is to be hoped that use of them
does not lead to any form of cancer. Certainly, at the time of writing
there has been no indication of this, but with a hormone product there must always be a chance of a long-term link with breast carcinoma.
Contraceptive implants do of course have side effects
(see below). But one good thing is that if you do encounter problems with
unwanted effects, you can just have the device taken out – and the side-effects
should stop almost immediately. (This is a big contrast with the contraceptive
injection – because once a jab is in, there’s nothing anyone can do to get it
out.)
What implants are available?
In the UK at the present time, there’s only one – and its name
is
Implanon
(introduced to Britain in 1999 though not to the USA until 2006). More details about this brand in a moment.
However, there used to be another one, called Norplant, which
consisted of six matchstick-like rods – and which lasted for five years. It was
withdrawn in 2001 (largely because of problems with side effects), and all Norplant rods should really by now have been removed
– because they’ve all run out of hormone!
If by any chance you still have a Norplant in your arm, then it
is almost certainly not protecting you against pregnancy any more. You should have
it removed when you can.
There is also an implant called Jadelle, which is used in some
countries – notably Bangladesh. It may come to the UK eventually.
So what is Implanon?
Implanon is about the size of a thin matchstick. It contains a
hormone called etonorgestrel. Most users have it inserted under the skin of
their left upper arm, not far above the elbow.
The ‘match’ can easily be felt, but it’s not very visible –
except to someone who is looking for it. There will be a tiny scar at the point
where the device was inserted, but unless something has gone wrong, this
shouldn’t be very visible either.
Implanon lasts for three years.
How is it put in?
The specially-trained doctor (or nurse) injects a little local
anaesthetic into your skin, and then pushes the tiny rod in, using a special
needle.
Because of the local anaesthetic, there should be very little
pain.
Traditionally, the site of insertion has been in your left upper arm (if you’re right-handed), in a groove between two of your muscles. In October 2008, the manufacturer's recommendation was changed. The Implanon should now be put in slightly lower – about 8 to 10 cm above your elbow.
Generally, the procedure takes no more than three minutes. If you
feel OK, you can go home immediately afterwards.
After the insertion about 3.6 per cent of women, get brusing, swelling, redness or soreness after insertion.
How effective is it?
At least 99 per cent – maybe more like 100 per cent. One recent
trial gave a failure rate of less than one tenth of one per cent during the
first year of use.
When could I have it done?
Generally, Implanon is inserted during the first five days after
the start of your period – mainly to ensure that you’re not pregnant. The
device can also be put in soon after childbirth, with the insertion usually
being carried out when baby is three to four weeks old.
The device does not interfere with breastfeeding, but it is known that a small amount of hormone passes into the breast milk.
Is there anybody who shouldn’t have an Implanon?
Yes. You shouldn’t have one fitted if you’re experiencing
undiagnosed vaginal bleeding, or if you have severe liver disease, or are
suffering from thrombosis. A history of certain types of cancer makes Implanon
inadvisable.
There are a few other medical conditions (including jaundice
and a past
history of ‘pregnancy itch’) which may make the doctor or nurse reluctant to
put in an Implanon; more details from them.
Also, Implanon has been linked with cysts in the ovary. So if
you’ve had an ovarian cyst, this is perhaps not the method for
you.
Very importantly, larger women may find that Implanon isn’t
‘strong’ enough to protect them against pregnancy. For example, if your Body
Mass Index is over 35kg./sq.metre, the doctors may advise you that you
shouldn’t rely on it during the third year of use, when it could be producing
less hormone. And if you are very big, you may not be able to use it at
all.
Does Implanon react/interfere with any drugs?
Not to the same extent that the Pill does. For example, you can
take antibiotics without lowering the efficiency of the implant.
However, its effectiveness can be reduced by certain pills,
notably ones for tuberculosis such as
rifampicin (Rifadin) and
rifabutin (Mycobutin) and some
drugs for epilepsy such as
phenytoin (Epanutin),
carbamazepine (Tegretol),
phenobarbital and
primidone (Mysoline).
Most important: the popular herb St John’s wort should not be
used by women who have an implant because the herb reduces the efficiency of the contraceptive.
What are the side-effects of Implanon?
There are quite a few, the main one being frequent or prolonged
vaginal bleeding – which may affect a fifth of all users. But some women get no
periods – and are very pleased about that!
Other possible side-effects include:
-
headache
-
spots
-
weight gain
-
breast tenderness
-
dizziness
-
depression
-
changes in level of
sexual desire (rare).
For a full list, read the product leaflet, or talk to the Family
Planning nurse or doctor.
Is it true that an implant can 'wander' around a woman’s
body?
Occasionally, an Implanon can’t be felt where it’s supposed to
be – ie under the skin of the upper arm.
In this event, you’d need an
ultrasound scan to
find the device. Frequently, the ultrasound reveals that the implant was simply
pushed in too deeply during insertion.
In other cases, the problem turns out to be that the woman has
just put on a bit of weight – so that the Implanon is now a little hidden by
fat.
In January 2005, a leading medical journal published a report of
two cases in which Implanons had managed to move a few inches upwards under the
skin (possibly as a result of vigorous exercise). This is not a serious
matter.
True ‘migration’ of the device within the body is very rare
indeed.
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Last updated 13.10.2008
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