ReviewIntrauterine device and upper-genital-tract infection
Section snippets
Background: biases in observational studies
Observational research has commonly found an increased risk of salpingitis or tubal infertility among IUD users. For example, the apparent increased risk of upper-genital-tract infection in some observational studies3, 4 suggested a causal association. However, this was because of the consistent presence of three types of bias: use of an inappropriate comparison group (women using contraceptives that lower the risk of PID), systematic overdiagnosis of salpingitis among IUD users, and inability
The IUD as a cause of PID
Foreign bodies in the skin dramatically reduce the bacterial inoculum required to cause infection. By analogy, some researchers have concluded that the presence of an IUD in the uterus lowers host resistance to infection.10 However, the uterus and the skin are very different organs.
If an IUD increases a woman's risk of upper-genital-tract infection and if her exposure to infection remains constant, then her risk of PID should remain raised throughout the duration of her IUD use. Evidence
The IUD tailstring and infection
The Dalkon Shield's multifilament tailstring could carry bacteria cephalad by capillary action.16 This has raised the possibility that monofilament tails might facilitate ascent of bacteria as well. Though numerous physical17 and bacteriological18 studies of monofilament tailstrings have been done, their relevance to the risk of infection is unknown. Clinical studies provide a better assessment of the potential risk of the tailstring.
Two types of evidence exist: the temporal relationship
Inserting an IUD in the presence of gonorrhoea or chlamydial infection
In settings where STDs are uncommon, upper-genital-tract infection associated with an IUD is rare. For example, in the large WHO report,7 4031 women in China had IUDs inserted but no case of PID occurred during 9197 woman-years of observation. By contrast, in Africa, where STDs are more prevalent, eight cases of PID occurred during 1292 woman-years of follow-up.
Carrying out an abortion in the presence of Neisseria gonorrhoeae or Chlamydia trachomatis increases the risk of postabortal
IUD use by women with HIV infection
Based on theoretical concerns, several international medical organisations38, 39 advise against IUD use by HIV-infected women. Two concerns predominate: a possible increased risk of PID because of immunosuppression; and a theoretical increase in the risk of female-to-male transmission of HIV via increased viral shedding or menstrual blood loss.
A cohort study in Nairobi, Kenya, suggests that IUDs may be safe in HIV-infected women who have access to care.32 Investigators followed 156 women with
Acquisition of gonorrhoea or chlamydial infection
Little is known about the potential for the IUD to influence the acquisition of cervical STD pathogens. A study from Sweden43 examined the risk of PID among women with cervical gonorrhoea. Even without controlling for potential confounding, the investigators found no significant increase in the risk of PID (confirmed by laparoscopy) among IUD users compared with women using neither an IUD nor oral contraceptives. However, in a cross-sectional study such as this, the timing of STD acquisition in
Levonorgestrel-releasing IUD and upper-genital-tract infection
Unlike oiher IUDs, ihe levonorgesirel-releasing inirauierine sysiem may lower ihe risk of pelvic inflammaiory disease, although daia are inconsisieni. A mullicenire randomised conirolled irial from Europe compared t he levonorgesirel IUD and ihe Nova T, a copper device. The cumulaiive 36-monih gross disconiinuaiion rales for PID were 0·5 and 2·0 per 100 women (p<0·02)49 and ihe 60-monih rales were 0·8 and 2·2 per 100 women, respeciively (p<0·01).50 Anoiher large randomised conirolled irial51
Treatment of upper-genital-tract infection in IUD users
Based on ihe foreign-body analogy, some have iheorised dial ihe presence of an IUD will impair ireaimeni of an upper-geniial-iraci infeciion. A laparoscopy sludy from Sweden52 found no significani difference in ihe degree of inflammation of ihe fallopian lubes among IUD users compared wilh women using neilher an IUD nor oral coniraceplion. The same held irue for eryihrocyie-sedimeniaiion rale and fever. Odiers have confirmed lhai ihe severily of PID is noi related lo use of an IUD.53
The limited
Infertility after IUD use
Many studies have examined fertility after IUD discontinuation. Numerous case-series reports55, 56, 57, 58, 59 have suggested a negligible effect of IUD use on fertility after discontinuation. However, without contemporaneous comparison groups, this evidence is weak.
Two large case-control studies60, 61 from the USA found an overall increase in the risk of confirmed tubal infertility of 2·0 to 2·6 fold after use of all types of IUDs, including Dalkon Shields. However, women who had used only a
Balancing risks and benefits
Unlike barrier contraceptives, IUDs do not protect women against STDs. Unlike combination oral contraceptives, most IUDs do not protect against PID that requires admission to hospital. Protection against infection, however, is not the purpose of contraception. The usual counselling for women at risk of acquiring an STD, independent of contraceptive choice, is to use condoms as needed. This is prudent advice for IUD users as well.
Modern IUDs, such as the copper T 380A and
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