Use of ultrasound in predicting success of intrauterine contraceptive device insertion immediately after delivery.

OBJECTIVES To assess by ultrasound examination the success of insertion of an intrauterine contraceptive device (IUD) immediately after delivery and to determine the optimal distance between the lower end of the IUD and the internal os in predicting successful retention of an IUD. METHODS This was a prospective study carried out between December 2012 and April 2013. Two ultrasound examinations, transabdominal and transvaginal, were performed prior to hospital discharge following delivery and again at 6 weeks following delivery in women who received a postpartum IUD. Distance from the internal os to the lower end of the IUD was measured at each examination and compared in unsuccessful and successful cases of postvaginal delivery (PVD) and post-Cesarean section (PCS) IUD insertion. Logistic regression and receiver-operating characteristics (ROC) curve analysis were used to determine the difference in success between the two modes of delivery and to determine the optimal cut-off of the internal os-to-IUD distance for successful retention, respectively. RESULTS Ninety-one women were included in the study, comprising 60 PVD and 31 PCS IUD insertions. Thirteen PVD (22.4%) and eight PCS (25.8%) IUDs were either expelled spontaneously or removed at the 6-week scan because of improper placement. Mean distance from the internal os to the lower end of the IUD on ultrasound examination immediately after insertion was significantly greater in successful cases than in those in which IUDs were subsequently expelled/displaced (mean difference after PVD insertion, 20.1 mm (P = 0.006); mean difference after PCS insertion, 10.3 mm (P = 0.05)). Logistic regression analysis demonstrated that mode of delivery was not independently associated with successful retention of the IUD (P = 0.72; OR, 0.831 (95% CI, 0.301-2.189)). The distance from the lower end of the IUD to the internal os measured at ultrasound examination prior to hospital discharge provided reasonable predictive accuracy for determining retention of the IUD, with an area under the ROC curve of 0.74 (95% CI, 0.60-0.88) and an optimal cut-off of ≥ 30 mm (sensitivity, 64.71% (95% CI, 52.17-75.92%) and specificity, 80.95% (95% CI, 58.09-94.55%)). CONCLUSIONS IUD insertion immediately postpartum is feasible but carries a substantial risk of unsuccessful IUD retention. Ultrasound examination after insertion of an IUD could be considered for predicting the success of IUD retention.