Territorial wars begin in the womb, according to incredible new MRI footage of twins jostling for a bit of legroom in utero.
Thanks to technology called "cinematic-MRI," doctors at Imperial College's MR Unit in London were able to capture moving images of the smaller twin kicking the larger twin to eke out some space.
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The larger twin eventually responds with a little push of its own.
"We haven't really been able to see before in such real-time complete pictures how twins interact and what this cine lets us do is see their positions in relation to each other and how much space they have, how much space they occupy, and how they might move around and push each other out of the way," Dr. Marisa Taylor-Clarke tells New Scientist.
The new method works by taking repeated images of the same "slices" of the body and stitching them together to create a moving image.
While fascinating, the footage could indicate some trouble for the smaller fetus. As the Christian Post reports, doctors use the cinematic-MRI when they fear one twin may be absorbing blood from the other.
Known as twin-to-twin transfusion syndrome, the twin on the losing end of the battle can be born with a host of symptoms, including anemia, dehydration, and paleness.
It's not smooth sailing either for the larger twin — or the "recipient twin" in medical terms. He or she is often born with too much blood, leading to elevated blood pressure and the risk of cardiac failure.
If left untreated, the babies are at high risk of dying from complications.
Dr. Taylor-Clarke tells Reuters that the cinematic-MRI is not used so much to diagnose the condition as to observe its consequences.
"[O]ne 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," she says.
"MRI can pick up signs of brain injury much earlier and in much greater detail than ultrasound can at the moment."
Doctors hope the MRI technology, which does not use radiation and is therefore much safer than a regular CAT scan, will help them identify ways to better treat the syndrome.
ABC notes that advanced laser surgery has recently been used to treat TTTS and give both twins a better shot at survival.
Let's hope these two make it out of the womb safely and in perfect health so that they only ever have to fight over toys and their parents' attention.