Fetuses yawn in the womb, according to new research

We know that unborn babies hiccup, swallow and stretch in the womb but new observational research concludes that they also yawn.

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.

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

But the new research clearly distinguished ‘yawning’ from ‘non-yawn mouth opening’ based on the duration of mouth opening. The researchers did this by using the 4D video footage 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 foetuses 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 fetal development, and as such could provide a further medical indication of the health of the unborn baby.