OC11.07: Increasing number of prior Caesarean deliveries associated with intrauterine device malposition and anatomical changes

To assess the impact of prior Caesarean deliveries (CD) on intrauterine device (IUD) position and uterine anatomy. Retrospective analysis of all pelvic scans for the assessment of IUD position from July 2012 to July 2014. Midsagittal images were evaluated for uterine position, flexion angle, Caesarean scar defect (CSD) size, and IUD location. The images were read by trained providers, who were blinded to subject's clinical and surgical history. Uterine flexion angle was measured between the axis of the proximal endometrium and the endocervix. Prominent CSD was defined as being >50% of the wall width. IUD malposition was defined as complete or partial IUD existence outside the endometrial cavity. Association between number of CD and sonographic findings was analysed. Of the 469 patients, 161 (34.3%) had history of CD: 103 (22.0%) had one, 44 (9.4%) had two and 14 (3.0%) had three or more CD. The prevalence of a prominent CSD increased with increasing number of CD (28.2% in women with one CD, 52.3% in women with two CD, and 35.7% in women with three or more CD, Chi-square, p = 0.028). A logistic regression model revealed a highly significant association of uterine retroflexion with increasing number of prior CD compared to no history of CD: 1 CD (OR = 2.66, 95% CI: 1.55, 4.55, p < 0.001), 2 prior CD (OR = 7.76, 95% CI: 3.94, 15.29, p < 0.001), 3+ CD (OR = 8.62, 95% CI: 2.84, 26.11, p < 0.001). Of the 400 (85.3%) subjects with anteverted uteri, 79 (19.8%) were found to have displaced IUDs. We also noted a significant association between IUD displacement and the number of CD (Chi-square, p = 0.002). We found a general trend of displaced IUDs and higher median flexion angle (Wilcoxon, p = 0.06). The number of prior CD is significantly associated with IUD malposition and uterine retroflexion. Higher order of prior CDs seems to impact the uterine flexion angle. This observation may have important clinical implications for providers when placing IUDs in women with prior CDs or noted to have higher median flexion angles.