How to choose the right contraception

What it is

An intra-uterine contraceptive device (IUCD) is inserted and retained within the uterine cavity to prevent pregnancy. Most are made from polyethylene, and contain copper, which is slowly released over several years. Most types of coil are kept in place within the uterine cavity as a result of their shape. One version, known as GyneFix, consists of six copper beads threaded onto a length of surgical thread, with no rigid polyethylene frame. This is inserted with a special applicator, so that a small 'knot' at the upper end becomes embedded into the muscle of the upper uterus, from which the thread is suspended within the uterine cavity. This is less likely to become dislodged or expelled than traditional designs of coil.

How it works

The IUCD is thought to prevent pregnancy by:

• producing a low-grade inflammation of the womb lining (endometrium) and Fallopian tubes, which interferes with sperm and egg transport, and also makes the womb lining inhospitable to a fertilised egg
  
• physically interfering with the implantation of a fertilised egg
  
• releasing copper ions, which are toxic to eggs and sperm.

The recommended life span of most coils is three to five years. Some latest-generation coils may be left in place for up to ten years.

The coil is an effective method of contraception, with a failure rate of less than 1% to 2%.

Pros

• Long-term, effective and reversible.
  
• Effective immediately after fitting.
  
• The method isn't related to intercourse.
  
• Can be used for emergency contraception in some cases.

Cons

• Must be inserted by a trained healthcare professional.
  
• May not be suitable for women who haven't had children.
  
• May cause heavy, painful periods.
  
• May become embedded in or perforate the womb, especially during insertion.
  
• May fall out.
  
• Can be difficult to remove, and may need surgery for removal.
  
• There's an increased risk of pelvic infection and of ectopic pregnancy.
  
• If the method fails, the device may lead to complications during pregnancy.