Uterine Perforation Rates for Levonorgestrel and Copper IUDs

IUDs are a safe and effective method of contraception, as well as an effective treatment of certain causes of heavy menstrual bleeding. Uterine perforation is a known risk of these devices, but the studies reporting incidence of this risk have produced conflicting results. However, no matter the numbers, the overall risk of uterine perforation with an IUD remains extremely low.

Today at the 2014 ACOG Annual Clinical Meeting, Klaas Heinemann, MD, PhD, of ZEG-Berlin in Germany, reported the final results of the European Active Surveillance Study for Intrauterine Devices (EURAS-IUD), a large, prospective, noninterventional cohort study of new users of levonorgestrel (LNG) IUDs and copper IUDs. Heinemann and colleagues undertook this study to determine if there were any differences in rates of uterine perforation between IUD types. This paper earned a second-prize designation from ACOG. The research was supported by an unrestricted grant from Bayer, the makers of Mirena, an LNG IUD.

The study involved more than 61,000 women from 6 countries-Germany, Austria, United Kingdom, Finland, Poland, and Sweden-who were new users of an IUD and was inclusive of repeat users of an IUD. Approximately 70% of the women used an LNG IUD and 30% used a copper IUD.

At 12 months, 92.9% of women with an LNG IUD and 87.5% of women with a copper IUD still had the device. Also at 12 months, 61 cases of uterine perforation occurred in the LNG IUD group and 20 cases occurred in the copper IUD group. First-time users had higher expulsion rates than repeat users.

Of the 81 women with uterine perforation, 64 women had risk factors for perforation, including breastfeeding (n=35), prostaglandin use before insertion (n=7), and previous use of general anesthesia (n=15). Based on these data, there is no clinically relevant difference in risk of uterine perforation between users of the LNG IUD and users of the copper IUD, with both groups having a relative risk hovering around 1/1,000 insertions.

However, there were notable differences in failure rates and ectopic pregnancy rates, said Heinemann. Unintended pregnancy occurred in 26 women with the LNG IUD and 92 women with the copper IUD, and ectopic pregnancy occurred in 7 women with the LNG IUD and 14 women with the copper IUD. He pointed out that although there were fewer users of the copper IUD (30% vs 70%), this group had more than 3 times the number of unintended pregnancies and double the number of ectopic pregnancies than the LNG IUD group.

The take-home: Uterine perforation rates related to IUD use are low and aren’t significantly different between IUD types. In terms of the differences in failure rates, Heinemann didn’t comment.