A British doctor has captured pictures and video showing that fetuses yawn in the womb. It was once thought that the fetuses were merely opening and closing their mouths but new technology allowed scientist Najda Reissland to be able to distinguish between the two actions.
According to Reissland, the pre-born yawn far more than they open their mouths. She speculates that yawning aids brain development.
Further reading: “When Fetuses Yawn In The Womb”