Birth control used by millions of women associated with life-threatening gut 'strangulation' complication

Two women nearly died after their birth control implants migrated into their abdomens and trapped loops of their bowels in a life-threatening 'strangulation.'

The patients had both used ring-shaped intrauterine devices (IUDs) to prevent pregnancy for more than 30 years - far longer than the maximum approved length of time of up to 10 years. 

Neither woman, who were 61 and 73, had their device removed at the recommended time, and in both cases, the anonymous patients went to the hospital with abdominal pain, nausea and vomiting.

It was then discovered that the IUDs had slowly eroded through the wall of their uterus, which thins with age, and migrated into the abdominal cavity.

There, the ring-shaped device created a deadly trap in which a loop of small intestine slipped through its center and became constricted, cutting off blood flow and causing tissue to die. Doctors had to remove up to two feet of intestine.

While IUDs are generally safe, complications, though rare, can be serious. The risk goes up when devices are left in after menopause because the shrinking uterus makes perforation more likely.

The two cases, reported by surgeons in China, occurred within six months of each other. The authors suggested this ‘cluster’ may signal a growing problem as populations age and more women live for decades with retained IUDs. 

Ring-shaped IUDs are used by 40 to 50 million women globally. They are an older form of the devices and less common in the US because they tend to cause problems later in life. 

Their blunt shape means they migrate more slowly than the sharper T-shaped IUDs used today.

Ring-shaped IUDs are also rigid and do not flex with the uterus. After menopause, as the uterus shrinks, the stiff ring can slowly wear through the thinning uterine wall over many years.

Once it escapes into the abdomen, a loop of intestine can slip through its hollow center and become trapped, cutting off blood flow and requiring emergency surgery.

In contrast, modern T-shaped IUDs are flexible and rarely cause this. If they migrate, they are more likely to directly puncture an organ rather than create a trap for the bowel.

While IUDs are generally safe and effective, the risk of serious complications rises significantly when devices are left in place after menopause because of the thinning of the uterine wall. 

One case study published in the American Journal of Case Reports details a 61-year-old woman who arrived at the emergency department complaining of severe abdominal pain, bloating, nausea and vomiting over the previous day.  

A CT scan revealed that her ring-shaped IUD had migrated out of her uterus and into her abdomen.

There, a loop of her small intestine had slipped through the ring’s center and become strangulated, cutting off its blood supply.

Surgeons rushed her to the operating room and found 30 centimeters, roughly 12 inches, of dead bowel. 

They removed the dead tissue and reconnected the healthy ends.

Just months later, a 73-year-old woman visited the same hospital with similar symptoms - nausea, vomiting and lower abdominal pain that had worsened over two days. 

Her CT scan told the same story as the first patient’s: a migrated ring IUD with a loop of intestine trapped inside. This time, surgeons found 50cm, or 20 inches, of dead bowel that had to be removed.

Both women recovered well after their surgeries.

IUDs work primarily by stopping sperm from reaching or fertilizing an egg, preventing pregnancy. 

Hormonal IUDs release a small amount of progesterone-like hormone that thickens cervical mucus, making it hard for sperm to enter the uterus, and thins the uterine lining, so a fertilized egg is less likely to implant.

Copper IUDs release copper ions, which are toxic to sperm, preventing fertilization.

Most IUDs are safe and effective for three to 10 years, depending on the type, and can be removed at any time.

Complications with IUDs are rare overall, affecting less than one to five percent of users. The most frequent issue is device expulsion, where the IUD slips out of place. This happens in about three to 11 percent of women over five years.

Far more concerning is uterine perforation — when the IUD pushes through the uterine wall. This is exceedingly rare, occurring in only one to two out of every 1,000 insertions; that is less than 0.2 percent.

While IUDs are highly effective at preventing pregnancy, if a pregnancy does occur with an IUD in place, there is a slightly higher chance it could be ectopic, meaning outside the uterus, though the absolute risk remains extremely low.

For the vast majority of women, IUDs are a safe and reliable form of birth control.