baby hiccups

There is something about baby hiccups that make adults smile. It might surprise them to find out that ultrasound scans reveal that when in the womb, baby hiccups start after just two months; indeed before any breathing movements appear. That suggests that hiccups in adults are just the remains of some primal reflex, which occur only when this brain circuit is accidentally triggered.

The purpose of baby hiccups, i.e. during pregnancy, remains unclear. Expectant mothers describe the hiccups as a rhythmic bumping sort of feeling. One theory is that the movements prepare babies' respiratory muscles for breathing after birth. Another is that they prevent amniotic fluid entering the lungs. They do drink amniotic fluid and this sometimes causes the same type of oesophageal reflex, leading to the baby hiccups.