IUD perforation is rare, but women should still know about it

Women who choose to use an intrauterine device, or IUD, for birth control should be aware of the very small possibility that the device could puncture their uterus. They should know how to recognize that circumstance if it occurs, according to a new study published in The Lancet.

The U.S. Food and Drug Administration mandated the study to evaluate women's risks when an IUD is placed in the year after giving birth and when an IUD is placed during the period that a woman is breastfeeding a baby. These results were compared, respectively, with non-postpartum insertions and insertions in non-breastfeeding individuals, explained UW Medicine's Dr. Susan Reed, the study's lead author.

Across the study cohort of 327,000 women, the percentage of perforation cases diagnosed within five years of IUD insertion was 0.6 %, the study concluded.

• The risk of perforation increased by nearly seven times if it was inserted between four days and six weeks postpartum, and increased by about one-third if inserted during the span of breastfeeding.
• The risk of an IUD-related perforation was relatively lower when inserted in women who were more than a year beyond delivery, in women who had never had a baby, and when the insertion occurred at delivery.

Reed said the study led Bayer Pharmaceuticals to update the "black box" warning on its Mirena IUD, providing greater precision to the existing warning language. The packaging instructions alert women to contact their doctor immediately if they experience symptoms associated with uterine perforations. The main symptoms are pain and change in bleeding patterns, Reed said.

"This study provides additional information on which patients may be at higher risk of perforation and which patients may need additional monitoring. It is a reminder to providers that the consent process is critical and that we should provide better instructions on what to watch for," said Reed, an OB-GYN with the University of Washington School of Medicine. Additionally, medical providers may ask patients who are experiencing symptoms to seek follow-up ultrasounds in clinic to ensure that the IUD is in the proper place.

Using health records, the study followed approximately 327,000 women age 50 or younger with IUD insertions from 2001 to 2018. Among the women, they identified 1,008 uterine perforations involving IUDs that contained either copper or a progesterone hormone. The postpartum cohort (within 12 months of childbirth) comprised approximately one-third of the women in the study. The data was collected from three healthcare systems: Kaiser Permanente Northern California, Kaiser Permanente Washington, and Kaiser Permanente Southern California.

Despite the slight increase of perforation when insertion occurs in breastfeeding women and in women with insertions between four days and six weeks postpartum, the benefits of effective contraception "should have little clinical impact," the report stated. "Perforation remains an incredibly rare event."

"The main takeaway is that follow-up may be warranted with these specific groups of patients," Reed said. "We want to stress to women that this is a safe option for contraception."

Copper and hormonal-based IUDs work by changing the way sperm cells move so they don't connect with the egg in the uterus. Worldwide 14% of women use IUDs, which are 99% effective at preventing pregnancy. In the United States, about about 10% of women use IUDs, according to the American Colleges of Obstetricians and Gynecologists.