Video appears to show twins fighting for space in womb

What really goes on when twins share a womb? If this video is any indication, it could be a similar to what happens once they're young children -- they fight.

The amazing images of twins in utero come from a study aimed at using MRI machines to diagnose a potentially deadly condition called twin-to-twin transfusion syndrome, Reuters reports.

The rare condition occurs only in identical twins, when blood from one twin moves into the other. That can significantly reduce the supply in the twin that loses the blood, causing him or her to be born smaller than their sibling, and with paleness, anemia and dehydration. The twin that receives the blood may be born larger than the other twin with increased blood pressure that may lead to heart failure.

The video was made at London's Center for Fetal Care, according to Reuters, and the so-called cinematic-MRI the hospital used was able to pick up the pictures of what appears to be unborn twins fighting for space in mom's womb.

"We use MRI in twin-to-twin transfusion syndrome, not so much for diagnosing it, which can effectively be done on ultrasound but more for looking at the consequences of it," Dr. Marisa Taylor-Clarke of the Robert Steiner MR Unit at Imperial College London, told Reuters. "So one of the problems with the imbalances of blood flow is that if you get a sudden shift of blood from one twin to the other, that can cause brain injury, so it can cause stroke or hemorrhage in one or both of the twins' brains. MRI can pick up signs of brain injury much earlier and in much greater detail than ultrasound can at the moment," she explained.

In June, NewScientist first reported on the video and Taylor-Clarke's research.

"A lot of the so-called videos in the womb are very processed, so they do a lot of reconstructing and computer work afterwards," Taylor-Clarke told NewScientist at the time. "These are the raw images that are acquired immediately."

Are these two twins duking it out in the womb for extra leg room? Watch the video above and see for yourself.

To see another visually-impressive use of cinematic-MRI machines, see a video that captured a live birth.