These devices consist of a plastic carrier wound with copper wire or fitted with copper bands.
The stated time when these devices should be replaced is stated in the respective SPC - most copper IUCDs should be replaced every 5 years although some devices have longer periods before requiring replacement e.g. TT380 Slimline is stated at 10 years.
A Cu-IUD (containing >=300 mm2 copper ) inserted at or after the age of 40 years can be retained until 1 year after the last menstrual period if this occurs when the woman is over the age of 50 years (2 years if under 50 years) (1)
Copper IUDs work primarily by inhibiting fertilisation due to direct toxicity (1)
- an inflammatory reaction within the endometrium may have an anti-implantation effect should fertilisation occur but an IUD is not an abortifacient (1)
- alterations in the copper content of cervical mucus are seen, which may inhibit sperm penetration (1)
Contraceptive efficacy (2)
- IUDs act by preventing fertilisation and inhibiting implantation
- licensed duration of use for IUDs containing 380 mm2 copper ranges from 5 to 10 years, depending on the type of device.
- pregnancy rate associated with the use of IUDs containing 380 mm2 copper is very low (fewer than 20 in 1000 over 5 years).
- no evidence of a delay in the return of fertility following removal or expulsion of IUDs
Risks and possible side effects (2)
- up to 50% of women stop using IUDs within 5 years; the most common reasons are unacceptable vaginal bleeding and pain.
- no evidence that IUD use affects weight.
- any changes in mood and libido are similar whether using IUDs or the IUS, and the changes are small
- risk of uterine perforation at the time of IUD insertion is very low (less than 1 in 1000)
- risk of developing pelvic inflammatory disease following IUD insertion is very low (less than 1 in 100) in women who are at low risk of STIs
- IUDs may be expelled but this occurs in fewer than 1 in 20 women in 5 years.
- risk of ectopic pregnancy when using IUDs is lower than when using no contraception.
- overall risk of ectopic pregnancy when using the IUD is very low, at about 1 in 1000 in 5 years.
- if a woman becomes pregnant with the IUD in situ, the risk of ectopic pregnancy is about 1 in 20, and she should seek advice to exclude ectopic pregnancy
Reference:
- FSRH Guidance (April 2015) Intrauterine Contraception
- NICE (September 2014). Long-acting reversible contraception (update)
- BNF 7.3
- Drug and Therapeutics Bulletin (1996); 34 (12): 93-5.