Sonning Common Health Centre

39 Wood Lane, Reading, RG4 9SW

Telephone: 0118 972 2188

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Coil IUD – Important Information

You have requested to have a coil fitted. In order to ensure that you understand what this involves, and that it is suitable for you, we request that you read the following:

Failure to read this information prior to your appointment could result in a planned procedure being cancelled.

You must refrain from intercourse or
use reliable alternative forms of contraception for at least 2 weeks prior to coming.


Problems that can occur with any IUD insertion:

• There is a small risk of ectopic pregnancy, a pregnancy occurring outside the womb. This
is less likely than if no contraception is used but more likely if there is a history of a
previous ectopic pregnancy or pelvic infection.

• Insertion and removal may cause some pain and bleeding.

• Insertion can precipitate fainting.

• Insertion can precipitate a seizure in an epileptic patient.

• IUDs increase the likelihood of pelvic infection which are more common in patients with
multiple sexual partners, frequent intercourse and young age. The Mirena/IUS
(progesterone-releasing IUD) has a much lower risk of infection. If you have a new
sexual partner or have had more than one sexual partner in the last 12 months you may
be at risk of chlamydia even if you have no symptoms, please discuss screening with
your nurse or doctor.

• Expulsion of the coil can occur. This is more likely in the first 24 hours and during the
first period. For this reason we recommend waiting for your six week check before
relying on it for contraception. Expulsion can cause pain and bleeding but can be
associated with no symptoms. We recommend also checking your strings to verify the
coil is in place.

• Perforation of the uterus or cervix may occur. This is more likely at insertion but is rare
occurring in 1 in 1000 patients. This may be associated with severe pain and continued

• Loss of threads can occur for various reasons but if you are unable to feel your threads
you should have your coil checked and not rely on it for contraception. Sometimes an
ultrasound scan is needed to locate it or check for expulsion.

• Pregnancy can still occur as no form of contraception is 100% effective it is less than 1
pregnancy per 100 woman years for the Mirena.

• When a non Mirena coil is fitted periods can be heavier and more painful due to the
presence of the coil.


Problems that can occur specifically with a Mirena IUD/IUS (progesterone-releasing IUD):

• It is quite normal to get irregular and persistent bleeding for 3-6 months after insertion
of a Mirena coil (20% of women). In most women this is just spotting and it settles down
after 6 months but in 3% of women it persists. 17% of women will become
amenorrhoeic meaning they have no periods at all for at least 3 months.

• Irregular bleeding may mask symptoms and signs of endometrial cancer.

• Functional ovarian cysts (i.e. non cancerous cysts) have been diagnosed in about 10-12%
of patients, which are also common with progesterone-only contraception taken by
mouth. In most cases they disappear spontaneously over 2 to 3 months but may
require further investigation or treatment. They can cause pelvic pain or pain with

• Low dose levonorgestrel (the progesterone in the Mirena) may affect glucose tolerance
and blood glucose concentration should be monitored in diabetic users.

• If pregnancy does occur with the Mirena coil the coil must be removed and termination
of the pregnancy considered, as there is an increased risk of spontaneous abortion and
premature labour.

• Other side effects reported include: headache (rarely migraine), lower abdominal pain,
back pain, skin disorders, mastalgia, and other benign breast conditions, vaginitis,
depression and other mood changes, nausea and oedema. Individual cases of weight
gain, hair loss, greasy hair and abdominal bloating have also been reported.

Information if having an IUD changed:

• If you are having a coil removed and another fitted you must refrain from intercourse or
use reliable alternative forms of contraception for at least 2 weeks prior to coming.
Alternatively you may attend with your normal menstrual period, ideally in the last 5
days. This is because removing a coil can cause the entrance of the womb to constrict
and this can mean it is not possible at that time to insert a replacement. Intercourse
that has occurred in the previous weeks could then result in pregnancy. We can give the
post coital contraceptive pill if the only occasion was within 72 hours of the coil
• We strongly advise taking ibuprofen (unless there is a reason you can not take it e.g. allergy,
severe asthma, previous stomach ulcer) before coming for any insertion of an IUD/coil but
particularly a change of coil.

Opening Times

  • Monday
    08:30am to 06:00pm
    8-8.30am and 6-6.30pm - Emergencies only
  • Tuesday
    08:30am to 06:00pm
    8-8.30am and 6-6.30pm - Emergencies only
  • Wednesday
    08:30am to 06:00pm
    8-8.30am and 6-6.30pm - Emergencies only
  • Thursday
    08:30am to 06:00pm
    8-8.30am and 6-6.30pm - Emergencies only
  • Friday
    08:30am to 06:00pm
    8-8.30am and 6-6.30pm - Emergencies only
  • Saturday
  • Sunday
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