Intrauterine device failure: relation to its location within the uterine cavity.

Abstract

To investigate the possible role of position of the intrauterine device (IUD) in accidental pregnancies. We examined the location of the IUD in 97 normal women 45-60 days post-insertion, and in 25 pregnant women with the device in situ. A cervically located IUD was identified in seven of 97 women (7.2%) after insertion and in 13 of 25 pregnant women (52%) with the device in situ. The odds ratio for a woman with an intracervical IUD to be pregnant compared with a woman with an IUD in the uterus was 13.93 (95% confidence limits 4.13-48.96). Sonographic follow-up of the pregnant women revealed no change in IUD location during early gestation. We suggest that cases of failed contraceptive action of the IUD may be secondary to a malpositioned device. A sonographic survey can identify displaced devices. Reinsertion of the IUD in such cases is recommended.