Fetuses yawn in the womb, according to new research

November 21, 2012, Durham University
Ultrasound pictures show difference in fetus yawning and other mouth openings
The ultrasound image shows mouth opening at 27.5 weeks gestation. Credit: Citation: Reissland N, Francis B, Mason J (2012) Development of Fetal Yawn Compared with Non-Yawn Mouth Openings from 24–36 Weeks Gestation. PLoS ONE 7(11): e50569. doi:10.1371/journal.pone.0050569

The 4D scans of 15 healthy fetuses, by Durham and Lancaster Universities, also suggest that yawning is a developmental process which could potentially give doctors another index of a fetus' health.

The study is published today (Nov 21) in the prestigious international academic journal, PLOS ONE. It was funded by the Economic and Social Research Council (ESRC).

While some researchers have suggested that fetuses yawn, others have disagreed and claim it is simple mouth opening.

But the new research clearly distinguished '' from 'non-yawn mouth opening' based on the duration of mouth opening. The researchers did this by using the 4D to closely examine all events where a mouth stretch occurred in the fetus.

Using their newly developed criteria, the research team found that over half of the mouth openings observed in the study were classed as yawns.

The study was carried out on eight female and seven male from 24 to 36 weeks gestation. The researchers found that yawning declined from 28 weeks and that there was no significant difference between boys and girls in yawning frequency.

Although the function and importance of yawning is still unknown, the study findings suggest that yawning could be linked to , and as such could provide a further medical indication of the health of the .

Ultrasound pictures show difference in fetus yawning and other mouth openings
This is an ultrasound showing yawn at 27.5 weeks gestation. Credit: Citation: Reissland N, Francis B, Mason J (2012) Development of Fetal Yawn Compared with Non-Yawn Mouth Openings from 24–36 Weeks Gestation. PLoS ONE 7(11): e50569. doi:10.1371/journal.pone.0050569

Lead researcher, Dr Nadja Reissland, of Durham University's Department of Psychology, said: "The results of this study demonstrate that yawning can be observed in healthy fetuses and extends previous work on fetal yawning. Our shows that yawning declines with increasing fetal age.

"Unlike us, fetuses do not yawn contagiously, nor do they yawn because they are sleepy. Instead, the frequency of yawning in the womb may be linked to the maturing of the brain early in gestation.

"Given that the frequency of yawning in our sample of healthy declined from 28 weeks to 36 weeks gestation, it seems to suggest that yawning and simple mouth opening have this maturational function early in gestation."

She added that yawning could be related to central nervous system maturation but further research involving mother and fetus would be required to examine this theory.

Explore further: More than a sign of sleepiness, yawning may cool the brain

More information: Reissland N, Francis B, Mason J (2012) Development of Fetal Yawn Compared with Non-Yawn Mouth Openings from 24 Weeks Gestation. PLoS ONE 7(11): e50569. dx.plos.org/10.1371/journal.pone.0050569

Related Stories

More than a sign of sleepiness, yawning may cool the brain

September 19, 2011
Though considered a mark of boredom or fatigue, yawning might also be a trait of the hot-headed. Literally.

Recommended for you

LincRNAs identified in human fat tissue

June 21, 2018
A large team of researchers from the U.S. and China has succeeded in identifying a number of RNA fragments found in human fat tissue. In their paper published in the journal Science Translational Medicine the group describes ...

Scientists solve the case of the missing subplate, with wide implications for brain science

June 21, 2018
The disappearance of an entire brain region should be cause for concern. Yet, for decades scientists have calmly maintained that one brain area, the subplate, simply vanishes during the course of human development. Recently, ...

Key molecule of aging discovered

June 21, 2018
Every cell and every organism ages sooner or later. But why is this so? Scientists at the German Cancer Research Center in Heidelberg have now discovered for the first time a protein that represents a central switching point ...

Compound made inside human body stops viruses from replicating

June 20, 2018
The newest antiviral drugs could take advantage of a compound made not by humans, but inside them. A team of researchers has identified the mode of action of viperin, a naturally occurring enzyme in humans and other mammals ...

Research reveals zero proof probiotics can ease your anxiety

June 20, 2018
If you're expecting probiotics to reduce your anxiety, it might be time to put down that yogurt spoon—or supplement bottle—and call a professional instead.

Long-term estrogen therapy changes microbial activity in the gut, study finds

June 20, 2018
Long-term therapy with estrogen and bazedoxifene alters the microbial composition and activity in the gut, affecting how estrogen is metabolized, a new study in mice found.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.