Association of Intrauterine Device Malposition With Previous Cesarean Delivery and Related Uterine Anatomical Changes.

OBJECTIVES: We sought to determine the association between intrauterine device (IUD) malposition and previous cesarean delivery (CD) and related uterine anatomical changes.

METHODS: A retrospective cohort of all persons with an IUD presenting for two- and three-dimensional pelvic ultrasonography over 2 years, for any gynecologic indication, was compiled. IUD malposition was defined as IUD partially or completely positioned outside the endometrial cavity. Uterine position, uterine flexion, and cesarean scar defect (CSD) size were assessed. Patient characteristics and sonographic findings were compared between those with normally positioned and malpositioned IUD. Primary outcome was the rate of IUD malposition in persons with and without a history of CD. Logistic regression analysis was used to control for potential confounders.

RESULTS: Two hundred ninety-six persons with an IUD had a pelvic ultrasound, 240 (81.1%) had a normally positioned IUD, and 56 (18.9%) had a malpositioned IUD. The most common location of IUD malposition was low uterine segment and cervix (67.9%). Malpositioned IUD was associated with referral for evaluation of pelvic pain (P = .001). Prior CD was significantly associated with a malpositioned IUD, after adjusting for confounders (aOR 3.50, 95% CI 1.31-9.35, P = .01). Among persons with prior CD, uterine retroflexion and a large CSD were independent risk factors for IUD malposition (aOR 4.1, 95% CI 1.1-15.9, P = .04 and aOR 5.4, 95% CI 1.4-20.9, P = .01, respectively).

CONCLUSIONS: Prior CD is associated with significantly increased risk of IUD malposition. Among persons with previous CD, those with a retroflexed uterus and a large CSD are more likely to have a malpositioned IUD.