The medicated intrauterine devices (IUDs), including the levonorgestrel-releasing IUD (LNG-IUD) (Mirena, Kyleena, Skyla, and Liletta) and the copper IUD (Cu-IUD; Paragard), are remarkably effective contraceptives. For the 52-mg LNG-IUD (Mirena, Liletta) the pregnancy rate over 6 years of use averaged less than 0.2% per year.1,2 For the Cu-IUD, the pregnancy rate over 10 years of use averaged 0.5% per year for the first 3 years of use and 0.2% per year over the following 7 years of use.3 IUD perforation of the uterus, expulsion, and malposition are recognized complications of IUD use. Our understanding of the prevalence and management of malpositioned IUDs is evolving and the main focus of this editorial.
Complete and partial uterus perforation
A complete uterine perforation occurs when the entire IUD is outside the walls of the uterus. A partial uterine perforation occurs when the IUD is outside the uterine cavity, but a portion of the IUD remains in the myometrium. When uterine perforation is suspected, ultrasound can determine if the IUD is properly sited within the uterus. If ultrasonography does not detect the IUD within the uterus, an x-ray of the pelvis and abdomen should be obtained to determine if the IUD is in the peritoneal cavity. If both an ultrasound and a pelvic-abdominal x-ray do not detect the IUD, the IUD was probably expelled from the patient.
Uterine perforation is uncommon and occurs once in every 500 to 1,000 insertions in non-breastfeeding women.4-8 The most common symptoms reported by patients with a perforated IUD are pain and/or bleeding.8 Investigators in the European Active Surveillance Study on Intrauterine Devices (EURAS) enrolled more than 60,000 patients who had an IUD insertion and followed them for 12 months with more than 39,000 followed for up to 60 months.7,8 The uterine perforation rate per 1,000 IUD insertions in non-breastfeeding women with 60 months of follow-up was 1.6 for the LNG-IUD and 0.8 for the Cu-IUD.8 The rate of uterine perforation was much higher in women who are breastfeeding or recently postpartum. In the EURAS study after 60 months of follow-up, the perforation rate per 1,000 insertions among breastfeeding women was 7.9 for the LNG-IUS and 4.7 for the Cu-IUD.8
Remarkably very few IUD perforations were detected at the time of insertion, including only 2% of the LNG-IUD insertions and 17% of the Cu-IUD insertions.8 Many perforations were not detected until more than 12 months following insertion, including 32% of the LNG-IUD insertions and 22% of the Cu-IUD insertions.8 Obviously, an IUD that has completely perforated the uterus and resides in the peritoneal cavity is not an effective contraceptive. For some patients, the IUD perforation was initially diagnosed after they became pregnant, and imaging studies to locate the IUD and assess the pregnancy were initiated. Complete perforation is usually treated with laparoscopy to remove the IUD and reduce the risk of injury to intra-abdominal organs.
Patients with an IUD partial perforation may present with pelvic pain or abnormal uterine bleeding.9 An ultrasound study to explore the cause of the presenting symptom may detect the partial perforation. It is estimated that approximately 20% of cases of IUD perforation are partial perforation.9 Over time, a partial perforation may progress to a complete perforation. In some cases of partial perforation, the IUD string may still be visible in the cervix, and the IUD may be removed by pulling on the strings.8 Hysteroscopy and/or laparoscopy may be needed to remove a partially perforated IUD. Following a partial or complete IUD perforation, if the patient desires to continue with IUD contraception, it would be wise to insert a new IUD under ultrasound guidance or assess proper placement with a postplacement ultrasound.
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