Contraceptive
injections
Contraceptive injections contain a progestogen hormone
which is similar to the natural progesterone that
women produce in their ovaries. There are 2 types
of injection. Depo-Provera protects you from pregnancy
for 12 weeks and Noristerat protects you for 8 weeks.
Both of these are very effective hormonal methods
of contraception. Depo-Provera is the most commonly
used in the UK.
How
effective is a contraceptive injection?
How do contraceptive injections
work?
Where can I get the injection?
Can anyone use a contraceptive
injection?
What are the advantages
of the contraceptive injection?
What are the disadvantages
of the contraceptive injection?
Are there any risks?
How does Depo-Provero affect
my bones?
Will the injection affect my
periods?
Will my weight be affected by
the injection?
When can I start using a contraceptive
injection?
When can I start the injection
after having a baby, miscarriage or abortion?
Can I use the injection
if I am breastfeeding?
How is the injection given?
Can anything make the
injection less effective?
Will I be able to choose which
injection I use?
Can I use the injection
if I am at risk of osteoporosis?
Should I have my bones scanned
before I start the injection?
What should I do if I think
that I am pregnant?
How long can I use the injection
for?
What should I do if I want to
stop using the injection or try to get pregnant?
If I have to go into hospital
for an operation should I stop using the injection?
How often do I need to see a
doctor or nurse?
How effective is a contraceptive injection?
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. If used according to the instructions,
injections are over 99% effective. This means
that less than 1 woman in 100 will get pregnant
in a year.
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How do contraceptive injections work?
The
main way they work is to stop your ovaries releasing
an egg each month (ovulation). They also:
•
Thicken the mucus from your cervix. This makes
it difficult for sperm to move through it and
reach an egg
• Make the lining of your
womb thinner so it is less likely to accept a
fertilised egg.
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Where can I get the injection?
Only
a doctor or nurse can give you the injection.
You can go to a family planning clinic or to the
doctor or nurse at your general practice. If you
prefer not to go to your own general practice,
or they don’t provide contraceptive services,
they will give you information about another practice
or clinic. All treatment is free and confidential.
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Can anyone use a contraceptive injection?
Most
women who want to can have a contraceptive injection.
Your doctor or nurse will need to ask you about
your own and your family’s medical history
to make sure the injection is suitable. Do mention
any illness or operations you have had. Some of
the conditions which may mean you should not use
the injection are:
•
you think you might already be pregnant
• you do not want your
periods to change.
• you have now or have
had in the past:
-
breast cancer
- unexplained vaginal bleeding (for example, bleeding
between periods or after sex)
- thrombosis (blood clots) in any vein
- a heart attack or stroke (serious arterial disease)
- high blood pressure
- diabetes with complications or diabetes for
more than 20 years
- active liver disease
- risk factors for osteoporosis (see Can I use
the injection if I am at risk of osteoporosis?).
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What are the advantages of the contraceptive injection?
•
You don’t have to think about contraception
for as long as the injection lasts.
• It doesn’t interrupt
sex.
• You can use it if you
are breastfeeding.
• Depo-Provera and Noristerat
are not affected by other medicines.
• It may reduce heavy painful
periods and help with premenstrual symptoms for
some women.
• It may give you some
protection against cancer of the womb.
• It gives some protection
against pelvic inflammatory disease.
• It is a good method if
you cannot use estrogens (hormones), like those
in the combined pill.
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What are the disadvantages of the contraceptive
injection?
• Your
periods may change in a way that is not acceptable
to you (see Will the
injection affect my periods?)
• Irregular bleeding may
continue for some months after you stop the injections.
Women may put on weight when they use Depo-Provera
(see Will my weight
be affected by the injection?).
• Other possible side-effects
include headaches, abdominal pain or discomfort,
dizziness, spotty skin, tender breasts, bloating,
and changes in mood and sex drive.
• The injection works for
12 or 8 weeks, depending on which type you have.
It cannot be removed from your body, so if you
have any side-effects, you have to be prepared
for them to continue during this time and for
some time afterwards.
• Your periods, and fertility,
may take a few months to return after stopping
Depo-Provera injections. Sometimes it can take
more than a year for your periods and fertility
to get back to normal.
• Contraceptive injections
do not protect you against sexually transmitted
infections, so you may have to use condoms as
well.
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Are there any risks?
• Using
Depo-Provera may affect your bones (see How
does Depo-Provera affect my bones?).
• Research about the risk
of breast cancer and hormonal contraception is
complex and contradictory. Current research suggests
that women who use hormonal contraception appear
to have a small increase in risk of being diagnosed
with breast cancer compared to women who don’t
use hormonal contraception. Further research is
ongoing.
• You can have an allergic
reaction to the injection, but this is very rare.
• As with any injection
there is a risk of a small infection at the site
of the injection.
Your doctor or nurse should discuss all risks
and benefits with you.
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How does Depo-Provera affect my bones?
Using
Depo-Provera affects your natural estrogen levels,
causing thinning of the bones. This is not normally
a problem for most women as the bone replaces
itself when you stop the injection and it does
not appear to cause any long-term problems.
Thinning of the bones may be more of a problem
for women who already have risk factors for osteoporosis
(see Can I use
the injection if I am at risk of osteoporosis?).
It is also a concern for young women under 19-years-old
as the body is still making bone at this age.
Although young women can use Depo-Provera, it
is recommended that they should first consider
all other suitable methods of contraception.
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Will the injection affect my periods?
Your
periods will probably change.
•
In some women periods will stop completely.
• Some women will have
irregular periods or spotting (bleeding between
periods), especially to begin with.
• Some women will have
periods that last longer and are heavier.
These changes may be a nuisance but they are not
harmful.
If
you do have prolonged bleeding it may be possible
for the doctor or nurse to give you some additional
hormone or medicine that can help control the
bleeding. They may also check that the bleeding
is not due to other causes, such as an infection.
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Will my weight be affected by the injection?
Not
all women put on weight with the injection and
some women lose weight. Some women using Depo-Provera
for 1 to 2 years have reported putting on up to
8lbs (just under 4kg). Further weight gain may
occur if Depo-Provera is used for longer periods
of time.
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When can I start using a contraceptive
injection?
You
will usually be given an injection during the
first 5 days of your period. You will be immediately
protected against becoming pregnant.
If
you have the injection on any other day you will
not be protected for the first 7 days, so you
will need to use another method of contraception,
such as condoms, during this time.
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When can I start the injection after having
a baby, miscarriage or abortion?
The
injection is usually given from 6 weeks after
you have given birth. Waiting until then makes
it less likely that you will have heavy and irregular
bleeding.
If
you want to use the injection before 6 weeks it
can be started 3 weeks (21 days) after you have
given birth. If you start the injection before
day 28 you will be protected from pregnancy immediately.
If it is started later than day 28 you will need
to use an additional method of contraception for
7 days.
The
injection can be started immediately after an
abortion or miscarriage if you were pregnant for
less than 24 weeks. You will be protected against
pregnancy immediately.
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Can I use the injection if I am breastfeeding?
It
is safe to use a contraceptive injection while
you breastfeed. It will not affect your milk supply
or harm the baby.
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How is the injection given?
The
hormone is injected into a muscle, usually in
your bottom. Depo-Provera can also sometimes be
given in the leg or the arm. Noristerat is a thicker
solution so you may find the injection is slightly
more painful when it is given. If you want to
carry on using this method of contraception, you
will need to have injections every 12 weeks if
you have Depo-Provera injections, or every 8 weeks
if you have Noristerat.
You
do not need to have a vaginal examination or cervical
smear to have the injection.
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Can anything make the injection less effective?
While
the injection is working there is nothing that
will make it less effective.
Injectable
contraception is not affected by:
•
prescribed medicines, including antibiotics
• any medicines which you
buy over the counter at a pharmacy in the UK
• diarrhoea
• vomiting
It is important to go back at the right time for
your next injection – every 12 weeks for
Depo-Provera or every 8 weeks for Noristerat.
Missing the next injection may mean that you are
no longer protected against pregnancy. To ensure
that you remain protected against pregnancy you
should not be more than 2 weeks late for your
next injection.
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Will I be able to choose which injection
I use?
It
is most likely that you will be offered the injection
Depo-Provera as Noristerat is usually only used
for short periods of time, for example, while
waiting for a sterilisation operation or for vasectomy
to become effective. Your doctor or nurse can
discuss with you which injection is most suitable.
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Can I use the injection if I am at risk
of osteoporosis?
If
you have risk factors for osteoporosis (thinning
of the bone) it is normally advisable to use another
method of contraception. Your doctor or nurse
will talk to you about this. These factors include:
•
a lack of estrogen due to early menopause (before
45 years)
• a lack of estrogen due
to missing periods for 6 months or more, as a
result of over-exercising, extreme dieting or
eating disorders
• smoking
• heavy drinking
• long-term use of steroids
• a close family history
of osteoporosis
• certain medical conditions
affecting the liver, thyroid and digestive system.
You can help to make your bones healthier by doing
regular weight-bearing exercise such as running
and walking, eating a healthy diet adequate in
calcium and vitamin D, and cutting down on drinking
alcohol and smoking.
The
National
Osteoporosis Society’s website
can give you more information about osteoporosis.
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Should I have my bones scanned before
I start the injection?
It
is not recommended that all women have a bone
scan before they start the injection. There may
be some women for whom it is useful, but these
are usually women who have been identified as
having risk factors for osteoporosis.
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What should I do if I think that I am
pregnant?
The
injection is a highly effective method of contraception.
If you have had your injections on time, it is
very unlikely that you will become pregnant. If
you think that you might be pregnant then you
can do a pregnancy test or speak to your doctor
or nurse as soon as possible. If you do get pregnant
while you are using the injection, it will not
harm the baby.
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How long can I use the injection for?
You
can continue to use Depo-Provera until the menopause,
provided there are no medical reasons not to use
it and you are not at risk of osteoporosis. If
you do use the injection long term you should
expect to have your risk factors for osteoporosis
re-assessed every two years. The doctor or nurse
may ask you about your lifestyle and discuss whether
it would be more suitable for you to use a different
method of contraception.
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What should I do if I want to stop using
the injection or try to get pregnant?
If
you want to stop the injection all you need to
do is not have your next injection. Your periods
and natural fertility may take a while to return
after you stop using the injection. However, it
is possible to get pregnant before you have seen
your first period. If you don’t wish to
become pregnant then you should use another method
of contraception from the day that your injection
would have been due. If you have sex without using
another method of contraception you may want to
consider using emergency contraception (see Emergency
contraception).
If
you want to try for a baby, it helps to wait for
one natural period before trying to get pregnant.
This means that the pregnancy can be dated more
accurately and you can start pre-pregnancy care
such as taking folic acid and stopping smoking.
You can ask your doctor or nurse for further advice.
Don’t worry if you do get pregnant sooner,
it will not harm the baby.
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If I have to go into hospital for an operation
should I stop using the injection?
No.
It is not necessary to stop the injection if you
are having an operation. However, it is always
recommended that you tell the doctor that you
are using the contraceptive injection.
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How often do I need to see a doctor or
nurse?
You
only need to go to the clinic or your general
practice when your injection is due. If you have
any problems between injections, you should contact
your doctor or nurse.
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