Ultrasound scans of faces in utero can distinguish between when a fetus yawns and when it just opens its mouth, according to research published November 28 in the open access journal PLOS ONE by Nadja Reissland from the University of Durham and colleagues at other institutions.
The researchers found that during the period between 24 to 36 weeks of gestation, they could distinguish between yawns and simple mouth openings on ultrasound images of fetal faces. They report that simple mouth openings occur less often than yawns and the frequency of these openings declines from 24 weeks of gestation onward. More than half of all mouth openings are yawns at 24 weeks of gestation, and the frequency of yawns begins to decline at a later stage (28 weeks onward).
The study suggests that trends in yawning behavior may potentially be used to track healthy fetal development. Reissland says, "Fetus yawning is not contagious, nor do they yawn because they are "sleepy". Instead, frequency of yawning in the womb might be related to activity-dependent brain maturation early in gestation."
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. doi:10.1371/journal.pone.0050569
Public Library of Science: http://www.plos.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Free-living songbirds show increased stress hormone levels when nesting under white street lights. But different light spectra may have different physiological effects as this study finds, suggesting that using street lights with specific colour spectra may mitigate effects of light pollution on wildlife
Scientists identify the condition aphantasia, in which people cannot create images in their head
The dust in our homes contains an average of 9,000 different types of fungi and bacteria, a study suggests.
A mosquito can bear up to 23 times its total body weight on each leg, which is crucial for landing on water – the insect's secret is way it stands
Tropical species with smaller geographical ranges are more likely to die out in a warming climate than those that can adapt by ‘invading’ new regions
Most people think of bacteria as germs, signs of filth, or unwanted bringers of disease. Slowly, that view …
The gloomy octopuses crowded at Jervis Bay, Australia, appear to spit and throw debris such as shell at each other in what could be an intentional use of weapons
Therapies based on hormones that make us more trusting enhance our natural placebo effect – a finding that could alter the way clinical trials are conducted
The blind, hairless babies born recently at Washington D.C.'s National Zoo are completely dependent on their mothers—who can sometimes accidentally crush them.
The poop-hoarding insects have an amazingly advanced internal GPS that allows them to navigate by day or night.