You probably have never heard of uterine inversion, and that’s a good thing: Uterine inversion is a rare complication of childbirth that occurs when part of the uterine wall collapses and turns inside out (in effect, like a sock being pulled inside out), sometimes even protruding through the cervix and into the vagina.

It’s considered an obstetric emergency: If left untreated, uterine inversion can lead to life-threatening hemorrhage and shock. 

What causes uterine inversion?

Although the exact causes aren’t completely understood, much of the time, uterine inversion is caused by the incomplete separation of the placenta from the uterine wall. As a result, the placenta pulls the uterus with it when it emerges from the birth canal.

The uterus is also more likely to invert if it’s overly relaxed, or if the umbilical cord is pulled too hard during delivery.

There are four grades of uterine inversion. They include:

  • Incomplete inversion. The top of the uterus has collapsed, but it hasn’t come through the cervix.
  • Complete inversion. The uterus is inside out and is coming out through the cervix.
  • Prolapsed inversion. The top of the uterus is coming out of the vagina.
  • Total inversion. Both the uterus and vagina protrude inside out. This is very rare.

About 90 percent of cases are complete or prolapsed. Most cases of inversion are acute uterine inversion, which means they happen within 24 hours of delivery.

How common is uterine inversion?

Uterine inversion is very rare. But there’s no clear consensus on how often uterine inversion occurs. Studies show uterine inversion rates vary from 1 out of every 3,500 deliveries to 1 in 20,000.

Who is most at risk of uterine inversion?

There are certain uterine inversion risk factors to be aware of. They include:

  • Macrosomia, or a very large baby

  • A uterine inversion during a previous delivery

  • An extended labor of more than 24 hours

  • Several previous vaginal deliveries

  • Severe preeclampsia

  • Use of drugs like magnesium sulfate (given to halt preterm labor)

  • Placenta accreta (the placenta has grown too deeply into the uterine wall)

More than half of the time, however, none of these risk factors are present.

What are the symptoms of uterine inversion?

It’s important to recognize the signs of uterine inversion so you can get prompt medical treatment. Uterine inversion symptoms include:

  • Abdominal pain

  • Excessive bleeding

  • Signs of shock, like very low blood pressure

  • In a complete inversion, the uterus will be visible in the vagina

Most uterine inversions happen at the time of delivery. If you have any of these symptoms, your doctor will do a physical exam to make sure your uterus is in its proper position. If it’s not clear, they will also order an ultrasound to confirm a uterine inversion diagnosis. 

How is uterine inversion treated?

There are three goals of treatment: return your uterus to its original position, stop bleeding and prevent the inversion from happening again. Options include:

  • Your doctor trying to fix your uterus by hand. This has to be done immediately, as your lower uterus and cervix contract over time, making this more difficult. Your practitioner may also give you an IV uterine relaxant such as nitroglycerin to soften the uterus, to make it easier.
  • Hydrostatic correction. If your doctor can’t manually "fix" your uterus, they may try to flushing saline solution into your vagina. The water pressure will "inflate" the uterus and props it back into position (hydrostatic correction).
  • Abdominal surgery. When your uterus turns inside out, it forms a cup-like shape. Your doctor will place clamps on the uterine ligaments that enter the cup, then gently pull on the clamps until the inversion corrects itself.

Once your uterus is put back into place, you’ll be given IV oxytocin to trigger contractions and stop the uterus from inverting again, as well as antibiotics to prevent infection.

Unfortunately, even with prompt treatment, you may still experience complications. The most common ones are postpartum hemorrhage, which happens in about a third of all cases, followed by the need for a blood transfusion. About 3 percent of the time, your doctor can’t manage your uterine inversion and will have to perform an emergency hysterectomy. 

What are the consequences of a uterine inversion?

Most women go on to get pregnant again, without experiencing a second uterine inversion. You should still let your provider know, as you’re theoretically at increased risk.

Uterine inversion is a potentially life-threatening complication of childbirth. But with prompt treatment, virtually all women recover and go on to have successful future pregnancies.