Malpositioned intrauterine contraceptive devices: risk factors, outcomes, and future pregnancies

To assess possible risk factors, management, and outcomes for women with malpositioned intrauterine contraception devices (IUDs).

This retrospective case-control study compared 182 women with malpositioned IUDs shown by ultrasonography at a single institution from 2003 to 2008 with 182 women with properly positioned IUDs. We evaluated whether insertion at 6-9 weeks postpartum, postabortion placement, breastfeeding, type of IUD, pregnancy history, leiomyomas, suspected adenomyosis, and indication for placement were associated with malpositioning. Our study had 70-99% power to detect whether postpartum placement was associated with an odds ratio (OR) of 2-3.

Malpositioned devices were noted on 10.4% of ultrasonography scans among women with IUDs having pelvic ultrasonography for any indication. Most malpositioned devices (73.1%) were noted to be in the lower uterine segment or cervix. Insertion of IUDs at 6-9 weeks postpartum was not associated with malpositioning (OR 1.46, 95% confidence interval [CI] 0.81-2.63). Among other possible risk factors examined, suspected adenomyosis was associated with IUD malpositioning (OR 3.04, 95% CI 1.08-8.52), whereas prior vaginal delivery (OR 0.53 95% CI 0.32-0.87) and private insurance (OR 0.38, 95% CI 0.24-0.59) were protective. Approximately two-thirds (66.5%) of malpositioned devices were removed by health care providers. There were more pregnancies within 2 years among those in the case group than those in the control group (19.2% compared with 10.5%, P=.046). All pregnancies were the result of IUD expulsion or removal, and none occurred with a malpositioned IUD known to be in situ.

Malpositioning of IUDs does not appear to be associated with insertion at 6-9 weeks postpartum. Women with malpositioned IUDs are more likely to become pregnant because of IUD removal without initiation of another highly effective contraceptive method.