When Fetuses Yawn In The Womb | WAMU 88.5 - American University Radio

NPR : News

Filed Under:

When Fetuses Yawn In The Womb

Why people yawn is a mystery. But yawning starts in the womb.

Past studies have used ultrasound images to show fetuses yawning, but some scientists have argued that real yawns were getting confused with fetuses simply opening their mouths.

So Nadja Reissland, a researcher at the University of Durham in the United Kingdom, used a more detailed ultrasound technique to get images of fetal faces that could distinguish a true yawn from just an open mouth.

"They seem to open their mouths widely much less often than they yawn," Reissland says.

What's more, she found that yawning was common at 24 weeks but then dropped to zero at 36 weeks, according to a report by Reissland and her colleagues in the journal PLOS ONE.

Reissland believes that fetal yawning may somehow help trigger brain maturation, by acting as a kind of self-stimulation for the developing fetus.

"It could be that yawning is something which you need in order to have a functioning brain, which is a hypothesis," she says, adding that she would like to compare yawning in healthy fetuses, like the ones she studied, with yawning in fetuses that have medical conditions.

Reissland says she suspects that yawning has a different function for adults than for fetuses. Most studies on yawning have focused on its contagious nature. But some research suggests that children are immune from "catching" another person's yawn until about five years of age.

And Reissland says one study showed that babies don't imitate their mother's yawns, even though babies do imitate mouth movements such as smiles and pursed lips. "How is it possible that these babies can imitate mouth movements, but they don't imitate the yawning?" Reissland wonders.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

WAMU 88.5

Art Beat With Lauren Landau, May 28, 2015

You can check out a photojournalism exhibit that peeks into the past and present of a U.S. region. A physical comedy troupe presents a classic play that skips through time. 

NPR

Bugs: Not What's For Dinner — Until They're Tastier, Maybe

A U.K. researcher says the environmental argument for eating bugs isn't working on its own. She says chefs and policymakers must "make insect dishes appeal as food, not just a way to save the planet."
NPR

5 Things You Should Know About George Pataki

For most voters, the name George Pataki might not ring a bell. But he was the last Republican elected to major statewide office in New York in more than 20 years. And he's running for president.
NPR

The Technology Of Books Has Changed, But Bookstores Are Hanging In

The debate over whether digital books are better continues. But in the age of Amazon, the number of independent booksellers is up. The revival is fueled, at least in part, by digital natives.

Leave a Comment

Help keep the conversation civil. Please refer to our Terms of Use and Code of Conduct before posting your comments.