Intra uterine contraceptive devices (IUCD)

IUS ‘Mirena’ coil– levanogestrel coated coil (NB the dose in the coil is much lower than that of the PoP

Mechanism of action

  • All IUCDs are though to have some action as a foreign body, stimulating leukocytes and prostoglandin release by the endometrium, which possibly provide a contraceptive effect
  • Progestogenic effects:
    • Thickening of the cervical mucus
    • thinning of the endometrium
    • (in some women) inhibition of ovulation

Pros and Cons

  • Pros
    • >99% effective
    • Can last long term (commonly 5 years but can be much longer)
    • Dual license for treatment of menorrhagia (reduces pain/flow)
    • High rate of amenorrhea
    • Can be used also as the progestogenic component of HRT (for up to 4 years)
    • Fully reversible
  • Cons
    • Requires specialist fitting
    • Early on, may cause irregular bleeding/side effects
    • ‘Lost threads’ – expulsion, malposition, perforation
    • ? PID
    • Ectopic pregnancy risk ?
    • ? Difficult to insert in nulliparous women (can be overcome with prostaglandin gel if need be)

Copper Coil

  • Lasts 5-10 years
  • Few problems or side effects
  • Avoids hormone treatments

Mechanism

  • Foreign body effect
  • Direct toxicity of Cu to sperm
  • Less sperm reach the upper genital tract
  • Altered uterine/tubal fluid

Pros and Cons

  • Pros
    • Lasts 5-10 years
    • Highly effective (>98%)
    • Fully reversible
    • Immediately effective
    • Also used for emergency contraception (very effective)
  • Cons
    • Heavy, painful periods
    • Irregular bleeding
    • Require specialist fitting
    • Insertion risks e.g. perforation, infection
    • ‘lost threads’
    • Risk of ectopic pregnancy
    • ? Difficulty to insert in nulliparous women

Contraindications to IUCDs

  • Absolute
    • Pregnancy
    • ? vaginal bleeding
    • Acute PID
    • Wilson’s disease/ CU allergy *
  • Relative
    • PHx of ectopic pregnancy *
    • Cervical/Vaginal infection
    • Fibroids
    • Anaemia *
    • Menorrhagia *
    • Recent history of PID *
    • Valvular heart disease *
    • ? nulliparity *
    • Multiple partners *
    • Immunosuppressed (steroids/HIV/immunosuppression) *

* Does not apply to Mirena coil

Infection and the IUCD

  • Coils do NOT CAUSE pelvic infection
    • Can make pre-existing infection worse
    • Highest risk 20 days post insertion- thereafter background risk
    • Treat prior to insertion if known

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