Clinical Context

Intrauterine devices (IUDs) are highly effective contraceptives used by 14% of women worldwide. Adverse events associated with insertion are rare and include uterine perforation, with an estimated rate of 1.1 to 3.6 per 1000 insertions.

Uterine perforation may be recognized at the time of insertion or later with symptoms of abdominal pain and cramps, or on speculum examination in an asymptomatic individual. Women and clinicians need information about benefits and risks for IUD use to make informed choices, but large, population-based studies are limited.

Study Synopsis and Perspective

Women for whom an IUD is inserted from 4 days to 6 weeks or less after giving birth, as well as those who are breastfeeding, are at higher risk for the contraceptive device puncturing their uterus, new research shows.

The risk for perforation was nearly 7 times higher for patients who received an IUD within that window than for those with an IUD who had never given birth or who were more than a year out from delivery, the researchers found. Healthcare providers should make patients aware of the heightened risk and should monitor these patients more closely, according to Susan Reed, MD, an obstetrician-gynecologist at the University of Washington School of Medicine, Seattle, who is the lead author of the new study.

"I'm a surgeon, and I like to be able to give people good information and good data about risks and benefits for their choices," Dr Reed told Medscape Medical News. "Uterine perforations related to IUDs are exceedingly rare, and to get good data or known risk factors, you need huge studies. This was the largest study done that really provided accurate information for patients and providers." The new study, which appears in a recent issue of the Lancet, also found that the risk for uterine perforation was lower if an IUD had been inserted immediately after delivery.

Dr Reed and colleagues analyzed data from the health records of 326,658 women ages 50 years or younger for whom an IUD was inserted between 2001 and 2018 at 4 healthcare systems. Nearly 30% of these patients received an IUD after giving birth.

The researchers identified a total of 1008 uterine perforations, for a cumulative incidence at 5 years of 0.6%. The cumulative incidence of uterine perforations was lowest in the group of women who were considered nonpostpartum; these women either received an IUD a full year after giving birth or had not given birth during the study period (0.29%; 95% confidence interval [CI], 0.26%-0.34%).

Women who received an IUD during the 3 days after delivery had a nearly 3-fold increased risk for an IUD perforation over nonpostpartum women.

In addition, the cumulative incidence of perforation was almost double among breastfeeding women compared with among women who were not breastfeeding. However, Dr Reed and coauthors noted that breastfeeding is highly beneficial for babies and that the risk for IUD perforation is relatively small.

Among the women who received an IUD after birth, Dr Reed's group found that 673 uterine perforations, of which 62% were complete, occurred in breastfeeding individuals, which was 37% more than for those who did not breastfeed.

Dr Reed said that the study provided some clarity on previous notions that women who had never given birth were possibly at higher risk for uterine perforation because of smaller uteruses.

"We used to be concerned that women who had never had a pregnancy at all might be at higher risk because their uterus was smaller, the cervix was tighter, and therefore perhaps they might have greater risks," Dr Reed told Medscape Medical News. "As a clinician and as a provider, it's pretty exciting to me to be able to tell our younger women who have never had a pregnancy that indeed their risk is lower than anybody else's."

The findings help women to make informed decisions, but overall, the benefits of IUDs outweigh the risks, said Monica V. Dragoman, MD, assistant professor of obstetrics, gynecology, and reproductive science at the Icahn School of Medicine at Mount Sinai, New York City.

"The likelihood of anyone experiencing these types of complications of that population level remains really low," Dr Dragoman said.

The findings also provide guidance for members of the healthcare team as to which patients should come in for additional follow-up visits after insertion, Dr Reed said.

"These are small risks, but it does tell us where we need to consider if there's a challenging insertion," Dr Reed said. "You're going to look with the ultrasound and make sure the placement looks right. You're going to give instructions that if the woman has pain or a change in her bleeding pattern, you want to see her back."

Patients should be aware of the symptoms of uterine perforation: an abrupt change in bleeding pattern and pelvic pain. Perforation correction typically consists of a minimally invasive surgical procedure.

The study was conducted as a result of an order from the US Food and Drug Administration to evaluate risks for uterine perforation for women who had received IUD’s.

Study authors received research funding from Bayer. Multiple authors are employees of Bayer. One study author has in the past received funding from CooperSurgical, Bayer Healthcare Pharmaceutical, and Merck & Co.

Lancet. 2022;399:2103-12.^[1]

Clinical Implications

• Risk for uterine perforation with IUD insertion 4 days to 6 or fewer weeks postpartum is nearly 7-fold that of insertion nonpostpartum but is still incredibly rare.
• Optimal IUD insertion timing should be based on individual desire for IUD contraception and patient convenience to ensure that IUD insertion can occur.
• Implications for the Health Care Team: Individuals at higher risk for uterine perforation should undergo careful follow-up, which may include ultrasound confirmation of IUD placement and advice to return for pelvic pain or change in bleeding pattern. Breastfeeding is highly beneficial for babies and the risk for IUD perforation is relatively small.

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