Contraception for women: an evidence based overview

I note from this article that the relationship between intrauterine
devices and ectopic pregnancy continues to cause confusion now just as it
did when my colleagues and I reported the relevant findings in our cohort
study in 1974 (Lancet 1974, 1, 495-98).

Amy et al state that " a meta-analysis of case-control studies showed
that ectopic pregnancy is not more common in women who conceive with an
intrauterine device in place." The meaning of this statement is not clear
to me but the clinically important fact is that if a woman with an
intrauterine device in situ presents with an accidental pregnancy she is
far more likely to have an ectopic pregnancy than a woman who has become
pregnant under other circumstances. Indeed, the review cited by Amy et al
gives the increase in risk as 10.6 fold under these circumstances. The
reason for this is that IUD's are far less effective at preventing ectopic
pregnancies than they are at preventing intrauterine pregnancies. Failure
to appreciate this fact could have disastrous consequences under some
circumstances.

Competing interests:
None declared