What 4 million women with an IUD need to know about real failure rates

IUD Failure Rate

‘First rigorous look at how long-term birth control methods perform’

Based on a new study, as many as 4 million women worldwide could find themselves pregnant on an IUD every year. Researchers were surprised to discover through this large-scale study that the generally accepted ultra-low failure rates of long-acting contraceptives have long been misrepresented, even by the CDC. 

An article published on Feb. 22, 2022, by the University of California San Francisco calls the study the “first rigorous look at how long-term birth control methods perform in the real world.” While the CDC claims the copper IUD failure rate is .8 percent and puts the hormonal IUD at between .1 and .4 of a percent, the “real world” failure results have turned out to be significantly higher. Women who felt confident of avoiding pregnancy with an IUD yet find themselves pregnant may think they’re one of the unlucky one-or-less percent, but they are actually in good company: closer to three percent.

In the study funded by Patient-Centered Outcomes Research Institute (RCORI), medical researchers followed over 83,000 California Medicaid clients who from 2008 to 2014 had received either a tubal ligation or an IUD. Within a year, analysis of the data found that 2.4 percent of those who had a hormonal IUD and 2.99 percent of those with copper IUDs had gotten pregnant. Of the women who had had a tubal ligation—previously considered “the gold standard” of effective pregnancy prevention—2.64 percent had become pregnant. 

“Women are told the chance of pregnancy with these contraceptives is one in 1,000 but we found much higher rates of pregnancy,” said Eleanor Bimla Schwarz, MD, first author on the study and professor of Medicine at UC San Francisco and chief of the Division of General Internal Medicine at Zuckerberg San Francisco General Hospital. “This real-world data is really important for clinical decision-making.”

This real-world data can also inform the choices of women in considering their options and the risks in relation to the less-stellar benefits of a contraceptive choice and the many risks and side-effects suffered by women with an IUD, whether copper or hormonal.

Unfortunately for those who do get unexpectedly pregnant with an IUD, sharing the uterus with an IUD comes with its own set of risks to both mother and baby, foremost of which is the risk of ectopic pregnancy (occurring in the fallopian tube), which results in the death of the baby and is life-threatening for the mother.  With 150 million women worldwide using IUDs, that could translate to over four million women who experience such a high-risk pregnancy.

Several women shared their stories on this site of having become pregnant after having an IUD inserted. A woman named Walaa reported on Aug. 28, 2021, that after having her first baby, she decided upon the copper IUD as her best option for preventing pregnancy.

“I thought I was going to be fine and there was nothing to worry about,” she wrote. “Within three months of having the IUD, I started having pregnancy symptoms and just like that I was pregnant.”

During a trip to the ER she was told that her IUD had moved behind her uterus and the baby was completely fine, but that removal of the IUD would cause her to lose the baby.

“I am currently dealing with the situation now and I am completely devastated and confused as I do not want to lose my baby,” she said.

While contraceptive failure rates are often presented in terms of “perfect use” and “typical use” to distinguish between actual method effectiveness and the results that our found in the “real world” factoring in human error, IUDs are considered fool-proof. While we can’t blame the user in the lowered success rates of the “set it and forget it” IUD, we can wonder why the truth hasn’t been studied carefully until now. 

The study also revealed tubal ligation to be correlated to even more infections, complications, and pain than the IUD, while being far less easily reversible, and be even less effective at preventing pregnancy than the hormonal IUD.

Fertility awareness methods (FAM) are effective, affordable, and natural approaches to managing fertility that are used around the world. Without any side-effects or health risks, the latest evidence-based FAMs track the various phases of a woman’s cycle each month through observable biomarkers, such as hormone levels (taken from a urine sample gathered first thing in the morning), body temperature (taken by mouth first thing in the morning), and patterns of cervical mucus or discharge (observable during bathroom visits throughout the day), or a combination of these signs.