Intrauterine System – IUS

aka Mirena Coil
This is a progesterone only contraceptive, and releases levonorgestrel directly into the uterine cavity. It is licensed for use as:
  • Contraceptive
  • Treatment for menorrhagia
    • Symptoms usually subside within 3-6 months of insertion
    • Many women will have lighter periods, and some will have none at all
  • Prevention of endometrial hyperplasia during oestrogen replacement therapy
  • It is recommended for use as a contraceptive device in women with heavy periods.
    • The reduction in menorrhagia may take 3-6 months to occur

Efficacy

  • Quoted as >99% effective
  • Described as: if taken correctly, then during the course of 5 years, <1% of women using the IUS will become pregnant

Mechanism

  • Prevents proliferation of the endometrium (making implantation difficult)
  • Thicken cervical mucus (creating a ‘plug) that sperm cannot penetrate
  • Suppresses ovulation (in some women, some of the time)
  • Long-term fertility is not altered
  • Lasts for 5 years
    • Can stay in for longer in the over 45’s
Advantages over the copper coil
  • Reduced risk of PID
  • Reduced risk of dysmenorrhoea
  • Reduced blood loss
  • Reduced risk of ectopic pregnancy (compared with copper coil)
    • Risk of ectopic pregnancy if pregnancy is present is still greater than general population
Advantages over progesterone only pill
  • Very few systemic effects
    • E.g.. drug interactions are negligible, and thus this is a suitable method for a woman taking a drug that interacts with progesterone.

Risks and Contraindications

  • Slight increased risk of ectopic pregnancy – although overall chance of pregnancy is very low!
  • Should be avoided for 5 years after breast cancer, due to effect of progesterone
    • However, systemic effects of progesterone are very small due to location of device.
  • Infection during first 20 days after administration (rare). Signs might include:
    • Pelvic / lower abdo pain
    • Discharge
    • Irregular bleeding
  • Expulsion and displacement – the coil can be moved by uterine contractions
  • Perforation (very rare) – usually occurs at the time of insertion.

Side effects

  • Changes in the pattern and duration of menstrual bleeding
    • E.g. spotting or prolonged bleeding
  • Mastalgia (breast pain)
  • Mood changes
  • Side effects reduce over time, and after several months may be negligible. Many women may have no bleeding at all – other may have light regular bleeding, and a small minority maintain an erratic pattern, but bleeding is still likely to be light.
  • Functional ovarian cysts – these are usually asymptomatic, and resolve spontaneously, but ultrasound monitoring is recommended

Prescribing

Fitting the coil

If there is risk / signs of infection, this should be treated. Often AB’s are given at the time of coil insertion.

  • Speculum examination is usually required to check for any structural abnormalities or infection that may prevent or contra-indicate insertion of the coil

Can be done in clinic or at the GP. Usually takes 15-20 minutes. Will be uncomfortable, some women may find it painful, and a local anaesthetic can be used. There may be light bleeding and some discomfort for the first few days
If there is any risk of pregnancy, a pregnancy test should be performed first.
If fitted in the first 5 days of the cycle, then is effective immediately
If fitted at another time in the cycle, condoms or another contraception need to be used for 7 days
The coil is usually checked 3-6 weeks after insertion to ensure it is properly in place.

  • After Pregnancy – Can be fitted 4 weeks after birth. Another method of contraception will be needed from day 21 until the coil is fitted
  • After abortion or miscarriage – Can be fitted immediately, and will be immediately effective.

Advising the patient

  • Show them how the coil sits in the uterus
  • Advise that there are two strings that poke down into the vagina. The patient can feel these strings in the vagina to know the coil is present
  • Rarely these may cause irritation (usually to the man) during sex, in which case, they can be cut shorter (but not too short – as you need them to get the coil out!)
  • Advise the patient that:
  • A normally fitted coil cannot be felt
  • If the women has any pelvic pain, or it feels like she is ‘sat on a match stick’ the coil may have slipped out (rare). She can check for herself by feeling for the strings, and she might feel part of the coil itself. She should make an appointment with the GP
  • Tampons can be used without issue

Removal of the IUS

  • Can be removed at any time
  • Fertility returns quickly
  • Sperm can live for up to 7 days. If you are planning on removing the coil, and do not want to become pregnant, additional contraception should be used in the 7 days before coil removal.

Intrauterine Device – IUD

aka Copper Coil

Contains only plastic and a copper coil
Two types:

  • Lasts 5 years
  • Lasts 10 years

Efficacy

  • Quoted as >99% effective
  • Described as: if taken correctly, then during the course of 1 year, <1% of women with an IUD will become pregnant

Mechanism

Is not fully understood, but thought to induce a mild inflammatory state in the uterus to prevent implantation, as well as copper being toxic to sperm.

Risks and Contraindications

Slight increased risk of ectopic pregnancy – although overall chance of pregnancy is very low!
Infection during first 20 days after administration (rare). Signs might include:

  • Pelvic / lower abdo pain
  • Discharge
  • Irregular bleeding
  • If symptoms of infection are present during this time, the woman should attend as a matter of emergency.

Expulsion and displacement – the coil can be moved by uterine contractions
Perforation (very rare) – usually occurs at the time of insertion.
Previous history of PID

Pre-insertion screening
The increased risk of infection within 20 days after insertion seen in these devices is believed to be related to pre-existing sexually transmitted infection. Therefore, those considered at high risk of TI should be screened for Chlamydia and gonorrhoea before insertion of the coil. This includes:

All women under 25
Women under 25 AND:

  • New partner
  • More than one partner in the last year
  • Their partner regularly has other partners

Side effects

Periods may be longer and heavier, particularly during the first few months. This can be addressed with

Tranexamic acid – 1g/6-8h for up to 4 days – an antifibrinolytic, can reduce menorrhagia by 50%
Mefanamic acid – 500mg/8h – an NSAID – antiprostaglandin – taken during periods of heavy bleeding, can reduce menorrhagia by 30%. Is also useful for dysmenorrhoea. 

Prescribing

Fitting the coil
Speculum examination is usually required to check for any structural abnormalities or infection that may prevent or contra-indicate insertion of the coil

Can be done in clinic or at the GP. Usually takes 15-20 minutes. Will be uncomfortable, some women may find it painful, and a local anaesthetic can be used. There may be light bleeding and some discomfort for the first few days

  • Women may be advised that 30mg of ibuprofen (NSAID) before the procedure can alleviate pain

Can be fitted at any time in the cycle, and is effective immediately
If there is any risk of pregnancy, a pregnancy test should be performed first.
If there is risk / signs of infection, this should be treated. Often AB’s are given at the time of coil insertion.

§ After Pregnancy – Can be fitted 4 weeks after birth. Another method of contraception will be needed from day 21 until the coil is fitted
§ After abortion or miscarriage – Can be fitted immediately, and will be immediately effective.

The coil is usually checked 3-6 weeks after insertion to ensure it is properly in place.

Advising the patient
Show them how the coil sits in the uterus
Advise that there are two strings that poke down into the vagina. The patient can feel these strings in the vagina to know the coil is present
Rarely these may cause irritation (usually to the man) during sex, in which case, they can be cut shorter (but not too short – as you need them to get the coil out!)
Advise the patient that:

  • A normally fitted coil cannot be felt
  • If the woman has any pelvic pain, or it feels like she is ‘sat on a match stick’ the coil may have slipped out (rare). She can check for herself by feeling for the strings, and she might feel part of the coil itself. She should make an appointment with the GP

Tampons can be used without issue

Removal of the IUD

  • Can be removed at any time
  • Fertility returns quickly
  • Sperm can live for up to 7 days. If you are planning on removing the coil, and do not want to become pregnant, additional contraception should be used in the 7 days before coil removal.

 

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