Physicians sometimes worry that women who have not given birth will have more difficulty with an intrauterine device (IUD), experiencing a higher expulsion rate. But the results of a recent study show that the opposite is true.

“For many years, IUDs were withheld from women who never had babies because of mythological concerns about infection, and the thought they had smaller uteruses and were more likely to expel the device,” says Mitchell D. Creinin, MD, professor of family planning and director of the Complex Family Planning Fellowship at University of California, Davis Health. “Instead, it’s the opposite: The more deliveries you have, the more likely you’ll expel IUDs. We know that if an IUD is not placed correctly, it will increase risk of expulsion, but it’s just more likely to occur if [someone] had a vaginal birth.”

Overall, the risk of expulsion is low — 3.8% over six years. Three-quarters of those expulsions occur in the first year.1

“After the first year, expulsion is very uncommon, and overall it’s uncommon,” he adds.

For every vaginal childbirth, the risk of IUD expulsion increases by 30%.1

The researchers found that women who had only vaginal delivery were more than twice as likely to experience IUD expulsion over 72 months as women who had not given birth, or who underwent a cesarean delivery. Women with a body mass index (BMI) of 30 or greater also experienced an IUD expulsion rate 2.6 times greater than the expulsion rate for non-obese women.

“People who had a baby before were more likely to have expulsion than those who did not have a baby,” Creinin says. “People who ever had a c-section had an expulsion rate pretty similar to those who never had a baby.”

In every analysis of the expulsion data, vaginal deliveries stood out as a chief risk factor. “What’s driving increased expulsion risk is people who had vaginal deliveries,” Creinin says. “The expulsion risk to people who had only vaginal deliveries was 7%; it was 5% at one year, and 7% at six years.”

Investigators conducted the study to give physicians more information about this IUD risk factor. “There are still doctors and providers out there who won’t give an IUD to women who have not had a baby, and their risk of expulsion is not higher than for those who had a baby,” Creinin says.

When women make decisions about which contraceptive method to use, they need these data to better inform their decisions. “It’s giving more information, being realistic,” he says.

Investigators analyzed data from the ACCESS IUS multicenter, Phase III, open-label clinical trial of the Liletta levonorgestrel 52 mg intrauterine system (IUS). The trial included 29 clinical sites that enrolled healthy, nonpregnant, sexually active women, ages 16 to 45 years, beginning in December 2009. Some had given birth previously, and some had not. There were follow-up visits three times in the first six months, and every six months after that. Participants were called at three-month intervals between visits.1

“We wanted to understand why expulsion occurs,” Creinin says. “If I place an IUD correctly in a woman with two vaginal deliveries and in a woman with a c-section, the woman who had vaginal deliveries may still expel the IUD. Obesity also comes into play — both independent.”

Clinicians need data to better inform patients. “When someone goes through the [IUD] procedure, you would hate for it to come out and for the woman to start bleeding and cramping,” Creinin says. “It’d be great to say to a patient, ‘These are the reasons why, and here are the factors associated with expulsion.’”

Expulsions also are much more common when the IUD is placed within minutes of a vaginal birth. For instance, when the IUD is placed right after a vaginal delivery, there is a 25% risk it will expel in the next six months. “There’s a one in four risk of expulsion,” Creinin adds. “If a woman shows up to every [prenatal] visit, you’re better off putting the IUD in after the follow-up visit than right away.”

But this depends on the woman’s social determinants of health and her commitment to returning to the clinic after she has given birth, he says.

The research also may suggest an opportunity for IUS companies to improve their products by developing IUDs for women who had a vaginal delivery. “As new IUDs are brought to market, they may need to design IUDs for this population,” Creinin says. “I hope further development of IUDs will take into account ways to minimize expulsion.”

As a woman’s BMI increases, so does the IUD expulsion risk. “It’s good for patients to know that if they’re obese and had vaginal deliveries in the past, their risk of expulsion is a little higher, and the doctor should let them know that,” Creinin says. “Be honest with patients, and tell them what the risk is, understanding that it changes based on patient characteristics.”

REFERENCE

  1. Gilliam ML, Jensen JT, Eisenberg DL, et al. Relationship of parity and prior cesarean delivery to levonorgestrel 52 mg intrauterine system expulsion over 6 years. Contraception 2021;S0010-7824(21)00054-8.