Using 4-D scan, unborn babies yawn repeatedly inside womb. A new study using high-resolution ultrasound footage, 4-D appears to confirm that they do yawn, and the most likely explanation is that it is linked to brain development.
Nadja Reissland, a researcher at the University of Durham department of Psychology in the United Kingdom concluded,
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. It could be that yawning is something which you need in order to have a functioning brain.”
13 For you created my inmost being;
you knit me together in my mother’s womb.
14 I praise you because I am fearfully and wonderfully made;
your works are wonderful,
I know that full well.