A trained doctor or nurse will
put the IUS into your womb. It slowly releases
the progestogen hormone. The IUS has two soft
threads at one end which hang through the opening
at the entrance of your womb (cervix) into the
top of your vagina. An IUS works for up to five
years. The IUS available in the UK is called Mirena.
Please use the list below if you
would like to jump directly to a particular topic.
How
effective is an IUS?
When will an IUS start to work?
How does an IUS work?
What are the advantages
of an IUS?
What are the disadvantages
of an IUS?
Can anyone use an IUS?
Where can I get an IUS?
How is an IUS put in?
What if I feel unwell after
the IUS is put in?
How will I know that the IUS
is still in place?
Is it safe to use tampons if
I have an IUS fitted?
How often do I need to see a
doctor or nurse?
When can the IUS be removed?
Will an IUS affect my periods?
What if I become pregnant
while I am using an IUS?
I've just had a baby. Can I use
an IUS?
Can I use an IUS after an
abortion or miscarriage?
How effective is an IUS?
How effective any contraceptive is depends on
how old you are, how often you have sex and whether
you follow the instructions.
If 100 sexually active women don’t
use any contraception, 80 to 90 will become pregnant
in a year. The IUS is over 99% effective. This
means of every 100 women who use an IUS, less
than 1 woman will get pregnant in a year.
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When will an IUS start to work?
Immediately, if it is fitted within the first
seven days of your menstrual cycle. If it is fitted
at any other time, you will need to use an extra
contraceptive method for the first seven days.
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How does an IUS work?
It makes the lining of your womb thinner so it
is less likely to accept a fertilised egg.
It also thickens the mucus from your cervix. This
makes it difficult for sperm to move through it
and reach an egg.
In some women it stops the ovaries releasing an
egg (ovulation), but most women who use an IUS
ovulate.
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What are the advantages of an IUS?
• It works for five years.
•
You don't
have to think about contraception for as long
as it works.
•
It doesn't
interrupt sex.
•
Your periods
usually become much lighter and shorter, and sometimes
less painful, so an IUS can be useful if you have
heavy, painful periods.
•
Your normal
fertility returns quickly when the IUS is removed.
•
Unlike some
methods of contraception, the IUS is not affected
by other medicines.
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What are the disadvantages of an IUS?
•
Most women
have irregular bleeding for the first three months
or so. This should settle down.
•
You may
get temporary side-effects such as headaches,
spotty skin and breast tenderness. These usually
go away after a few months.
•
Some women
may have cysts on their ovaries in the first few
months. These are not dangerous and do not usually
need to be treated. Often there are no symptoms,
but some women may have pelvic pain. These cysts
usually disappear without treatment.
•
There is
a very small chance of you getting an infection
during the first 20 days after an IUS is put in.
You may be advised to have a check for any possible
existing infection before an IUS is fitted.
•
An IUS does
not protect you against sexually transmitted infections,
so you may need to use condoms as well.
•
The IUS
can be pushed out by your womb (expulsion) or
it can move (displacement). This is more likely
to happen soon after it has been put in and you
may not know it has happened. This is why your
doctor or nurse will teach you how to check your
IUS threads every month.
•
It is not
common, but there is a risk that an IUS might
go through (perforate) your womb or cervix when
it is put in. This may cause pain, but often there
are no symptoms. If this happens, the IUS may
have to be removed by surgery. The risk of perforation
is low when an IUS is fitted by an experienced
doctor or nurse.
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Can anyone use an IUS?
Most women who want to use an IUS can do so, including
women who have never been pregnant and women who
are HIV positive. Your doctor or nurse will need
to ask you about your own and your family's medical
history. Do mention any illness or operations
you have had. Some of the conditions which may
mean you should not use an IUS are:
•
you think
you might already be pregnant
•
you have now or have had in the
past:
- cancer of the womb or ovary,
or breast
- active liver disease
- unexplained bleeding from your vagina (for example,
between periods or after sex)
- a heart attack, stroke (severe arterial disease)
or thrombosis (blood clots)
- an untreated sexually transmitted infection
or pelvic infection
- problems with your womb or cervix.
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Where can I get an IUS?
You can go to a family planning clinic, sexual
health clinic or to your general practice. Some
GPs and practice nurses will fit an IUS, but not
all. All treatment is confidential and free.
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How is an IUS put in?
An IUS is best fitted during the first seven days
of your menstrual cycle, but it can be fitted
at any time. The doctor or nurse must make sure
there is no chance of you being pregnant. They
will examine you internally to find the position
and size of your womb before they put in an IUS.
Sometimes they will check for any possible existing
infection. It is best to do this before the IUS
is put in. Sometimes antibiotics may be given
to you at the same time as fitting the IUS.
Fitting an IUS takes about 15-20
minutes. It can be uncomfortable, or painful for
some women, and you might want to have a painkiller
or local anaesthetic. Your doctor or nurse should
talk to you about this beforehand. You may get
a period-type pain after the IUS is fitted. Painkillers
can help with this.
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What if I feel unwell after the IUS is
fitted?
If you feel unwell and have any pain in your lower
abdomen, with a high temperature or a smelly discharge
from your vagina in the first three weeks after
the IUS is fitted, see a doctor or go back to
the clinic where it was fitted as soon as possible.
You may have an infection.
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How will I know that the IUS is still
in place?
An IUS has two threads attached to the end that
hang a little way down from your womb into the
top of your vagina. The doctor or nurse will teach
you to feel for the threads to make sure the IUS
is still in place. You should do this a few times
in the first month and then after each period
or at regular intervals.
It is very unlikely that an IUS
will come out, but if you cannot feel the threads
or if you think you can feel the IUS itself, you
may not be protected against pregnancy. Use an
extra contraceptive method, such as condoms, and
see your doctor or nurse straight away. If you
had sex recently, you might need to use emergency
contraception.
Rarely, your partner may say he
can feel the threads during sex. If this is the
case, get your doctor or nurse to check the threads.
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Is it safe to use tampons if I have an
IUS fitted?
Yes, you can use either tampons or towels during
your periods.
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How often do I need to see a doctor or
nurse?
You need to have your IUS checked by a doctor
or nurse three to six weeks after it is put in.
The IUS can stay in for five years. If you have
any problems you can go and see your doctor or
nurse at any time.
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When can the IUS be removed?
A trained doctor or nurse can take out the IUS
at any time, by pulling gently on the threads.
If you are not going to have another IUS put in,
and you don’t want to become pregnant, use
an extra contraceptive method, such as condoms,
for seven days before the IUS is taken out. This
is to stop sperm getting into your body. Sperm
can live for up to seven days inside your body,
and could fertilise an egg once the IUS is removed.
Your usual fertility returns quickly after the
IUS is taken out. You will usually have a period
within a month or so.
If you want to try for a baby
start pre-pregnancy care such as taking folic
acid and stopping smoking. You can ask your doctor
or nurse for advice.
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Will an IUS affect my periods?
Yes. At first there is usually irregular or longer
bleeding. Most women find that after about three
months, their periods become lighter than usual.
They may continue to be irregular and many women
find that their periods stop altogether. If this
happens to you, do not worry as it is perfectly
healthy. When the IUS is taken out your periods
will return to how they were before it was put
in.
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What if I become pregnant while I am using
an IUS?
Very few women become pregnant while using an
IUS. If you do become pregnant, your doctor or
nurse will need to discuss the situation with
you and take out the IUS.
If you do become pregnant there
is a small increased risk of you having an ectopic
pregnancy. An ectopic pregnancy develops outside
your womb, usually in a fallopian tube. If you
think you might be pregnant or have a sudden or
unusual pain in your lower abdomen, seek medical
advice as soon as possible. This might be the
warning sign of an ectopic pregnancy.
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I've just had a baby. Can I use an IUS?
An IUS is usually put in from four weeks after
a vaginal or caesarean birth. You will need to
use another method of contraception from three
weeks after the birth until the IUS is put in
and for seven days afterwards. An IUS can be used
while you are breastfeeding.
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Can I use an IUS after an abortion or
miscarriage?
An IUS can be put in immediately after an abortion
or miscarriage if you were pregnant for less than
24 weeks. If you had a medical abortion (using
pills) an IUS should be fitted in the first two
days after the abortion is complete otherwise
you will need to wait for four weeks. If it is
not fitted immediately, you will need to use another
method of contraception until the IUS is put in
and for seven days afterwards.
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