Intra-Uterine Devices

An intrauterine device is an object inserted through the cervical canal by a medical practitioner and placed in the uterus to prevent pregnancy. It has threads which hang down into the vagina, which a woman can feel using her fingers to make sure that the device is correctly positioned. Different IUDs are licensed to be left inside the uterus for periods ranging from 3 years to 8 years (depending on the type of IUD). It prevents pregnancy by impairing the viability of the sperm and ovum through the alteration of the fallopian tube and uterine fluids. This reduces the chances of the ovum and sperm from meeting, thus impeding fertilisation. The IUD also causes a foreign body reaction which irritates the lining and wall of the uterus, making it hard for an embryo to implant.

There are over 10 different kinds of copper IUDs available. Recently a new IUD system has been introduced known as an intra-uterine system (IUS) which works with a hormone (progestogen), has fewer side effects, increased efficacy and lasts up to 10 years. These are described further down in a section dedicated to hormonal contraception. The decision of which IUD to insert will depend on the woman and the size of her uterus.

An IUD may be removed at any time if a woman does not mind becoming pregnant. An IUD is removed by a medical practitioner who visualises the IUD threads in the vagina and gently pulls out the IUD. It is usually advised that IUDs are removed 1 year after the menopause, because there is concern that an IUD may cause pus in the uterus.

Efficacy

The IUD is from 98% to nearly 100% effective in preventing pregnancy, depending on the device. Newer IUDs have failure rates of less than 1 per 100 after 1 year of use.

Disadvantages

  • Heavy and prolonged menstrual periods
  • Excessive menstrual pain
  • Slightly increased risk of ectopic pregnancy if there is an IUD failure
  • Increased risk of pelvic infection
  • Expulsion of the IUD
  • Perforation of the uterus, bowel and bladder
  • Malposition of the IUD
  • Pregnancy caused by expulsion, perforation, or malposition.


Advantages

  • Effective immediately
  • No drug interactions
  • Reversible and highly effective
  • Does not interfere sexual intercourse


Absolute contraindications

  • Pregnancy
  • Undiagnosed genital tract bleeding
  • Previous ectopic pregnancy
  • Pelvic or vaginal infection; once treated an IUD may be fitted
  • Abnormalities of the uterus existing since birth (example a bicornuate uterus)
  • Allergy to components of the IUD, e.g. Copper
  • Wilson’s disease
  • Heart valve replacement or previous history of  bacterial endocarditis because of increase risk of infection
  • HIV and AIDS because of reduced immune system and increased risk of infection


Relative contraindications

  • History of pelvic infection
  • Excessive menstrual pain and/or heavy and prolonged menstrual periods
  • Fibroids and endometriosis.