Intrauterine devices and the risk of uterine perforations: final results from the EURAS-IUD 5 years study

Abstract

Objectives: Uterine perforation is a potentially serious complication of intrauterine device (IUD) use. The aim of the study was to determine the uterine perforation rate among women using IUDs. Methods: We conducted a comparative, multinational, prospective, noninterventional cohort study among new users of LNG-IUDs and copper IUDs. The combined cohort in the 5-year follow-up included 39,000 women in six European countries. The study was conducted from 2006 to 2015. Both the women and their treating physicians received a follow-up questionnaire 12 months after enrollment. In addition, women were contacted again after 5 years. All patient-reported outcomes of interest were validated with the treating physicians. The analysis was based on logistic regression models. Results: In total, 39,000 women were included in the 5-year analysis (71% used LNG-IUDs, and 29% used copper IUDs). In the last interim analysis in September 2015, perforations occurred among 49 LNG-IUD users [1.8 per 1000 insertions (95% CI, 1.4–2.4)] and among 16 copper IUD users [1.5 per 1000 insertions (95% CI, 0.8–2.4)]. The odds of perforation, adjusted for age, BMI, breastfeeding and parity, were higher among LNG-IUD users than among copper IUD users (OR, 1.6; 95% CI, 0.9–2.8). None of the perforations led to serious illness or injury to intraabdominal or pelvic structures. Conclusions: Perforation rates for intrauterine devices are low. The adjusted OR for perforation comparing LNG-IUD and copper IUDs was 1.6. An association of this magnitude identified in observational research is too low to discriminate among bias, confounding, causation and chance as alternative explanations. Perforation rates were significantly higher among women breastfeeding at the time of insertion.