An inverted uterus looks like the uterus has turned inside out, similar to pulling a sock through itself. The top of the uterus (the fundus) collapses inward and pushes down through the cervix, sometimes protruding into or beyond the vagina. What’s visible is a smooth, round, fleshy mass where the inner lining of the uterus is now on the outside. This is a rare but serious complication that almost always happens right after childbirth.
What It Looks Like Physically
Normally, the uterus is a hollow, pear-shaped organ with a rounded top (the fundus) sitting above the cervix. During inversion, that rounded top folds inward and descends, creating a bulging mass that can range from barely noticeable to fully visible outside the body. The placenta may still be attached to the mass, making it appear dark red and bloody.
On a physical exam, one of the key clues is that the fundus can’t be felt through the abdomen where it should be. Instead of a firm, round top of the uterus under the belly button, there’s a dimple or indentation, or the fundus simply isn’t palpable at all. Inside the vagina, a soft, globular mass is present that wasn’t there before delivery.
Degrees of Inversion
Uterine inversion is classified into stages based on how far the fundus has descended:
- Incomplete (first degree): The fundus has collapsed inward but hasn’t passed through the cervix. It sits like a dent or dimple inside the uterine cavity. This is the hardest stage to see directly because the mass stays inside the uterus.
- Complete (second degree): The fundus has pushed all the way through the cervix and now sits in the vagina as a visible round mass.
- Prolapsed (third degree): The inverted uterus extends beyond the vaginal opening and is visible outside the body.
- Total (fourth degree): Both the uterus and the vaginal walls have turned inside out, with the entire structure protruding externally.
What It Looks Like on Ultrasound
Imaging is not usually needed because the diagnosis is typically obvious on physical exam. But when the situation is unclear, ultrasound reveals several distinctive signs. The normal smooth, curved outline of the fundus disappears. Instead, a round, solid-looking mass (the inverted fundus) appears inside the uterine cavity or vagina.
Radiologists look for three specific markers. The first is a mirror image of the uterus, where the organ appears to project downward into the vagina instead of sitting upright. The second is a false stripe where the two inner surfaces of the uterus press together, mimicking what normally looks like the uterine lining. This can appear Y-shaped. The third is called a “target sign,” where a cross-section shows the inverted fundus as a central bright circle surrounded by a darker ring of fluid between the displaced tissue and the vaginal wall.
MRI can also confirm the diagnosis and produces clearer images of the anatomy, but it’s rarely used given the urgency of the situation.
Symptoms That Accompany the Appearance
The visual appearance of the mass is usually accompanied by heavy bleeding, which can be severe and rapid. Many women also experience sudden, deep pelvic pain and a sensation of something “falling” or bearing down. Blood pressure can drop quickly, and some women go into shock not just from blood loss but from a nerve response triggered by the uterus being pulled. This combination of hemorrhage and cardiovascular collapse is what makes uterine inversion dangerous. Left unrecognized, it can be fatal.
What Causes It
Uterine inversion happens almost exclusively after delivery, typically during the third stage of labor when the placenta is being delivered. Several factors raise the risk:
- Excessive traction on the umbilical cord before the placenta has naturally separated
- Fundal pressure applied too forcefully to help deliver the placenta
- Placenta accreta, where the placenta grows too deeply into the uterine wall and pulls the fundus with it during delivery
- Uterine atony, where the uterus fails to contract firmly after birth, leaving it soft and vulnerable to collapsing
- A short umbilical cord
- A larger-than-average baby
- Rapid or prolonged labor
- Prior uterine inversion or uterine surgery
First-time mothers and those who used fertility treatments also appear to have slightly higher risk, though inversion remains rare overall.
How It’s Corrected
Speed matters. The sooner the uterus is pushed back into place, the easier it is to do. Within the first few minutes, the cervix hasn’t yet clamped down around the inverted tissue, so a provider can manually push the fundus back up through the cervix and into its normal position. This is done by placing a hand inside the vagina and applying steady upward pressure on the center of the mass. The goal is to reverse the inversion in the opposite order it occurred, pushing the part that came through last back first.
If too much time has passed, the cervix contracts around the inverted tissue and traps it, making manual replacement much harder. Medications that relax the uterus may be given to loosen the cervical ring enough to allow repositioning. Once the uterus is back in place, other medications are used to make it contract firmly and stay in position.
In rare cases where manual techniques fail, surgery is required. This involves an abdominal approach where the surgeon pulls the fundus back into position from above, sometimes making a small incision in the cervical ring to release the trapped tissue. Most women recover well after successful correction, though close monitoring for continued bleeding is essential in the hours that follow.