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/.

NPR

In Tom Hanks' iPad App, Typewriters Make Triumphant Return (Ding!)

For iPad users who are nostalgic for the clickety-clack of keystrokes and "ding!" of the carriage return, Hanks has created Hanx Writer, an app that simulates using a typewriter.
NPR

New U.S. Rules Protect Giant Bluefin Tuna

To reduce the number of giant bluefin tuna killed by fishing fleets, the U.S. is putting out new rules about commercial fishing in the Gulf of Mexico and parts of the western Atlantic.
WAMU 88.5

Jury Deliberating 14 Counts In McDonnell Trial

As of Tuesday afternoon, there is no word yet from the seven men and five women who are deliberating 14 separate counts against the McDonnells.
NPR

The Troubling Implications Of The Celebrity Photo Leak

To learn more about the recent celebrity photo hack, Melissa Block speaks with Matthew Green of Johns Hopkins University. They discuss how the photos might have been obtained.

Leave a Comment

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