Did science just solve newborn hiccups?

Science may have finally determined the answer to the age-old question of why babies get hiccups so often. New parents often note that newborns hiccup several times per day. Sometimes, they hiccup so often that parents become concerned their babies are uncomfortable, even if they aren’t. Pregnant women will even comment that they can feel hiccups in the womb beginning many weeks before birth.

Hiccups are the sudden, unexpected contraction of an important muscle called the diaphragm. The diaphragm is an important muscle that separates the thorax, or chest cavity, from the abdomen. When the diaphragm contracts, the volume of the thorax increases and air is brought into the lungs through the mouth or nose. When it relaxes, the thorax is squeezed down and old air is expelled from the lungs.

A study published in the journal Clinical Neurophysiology may have clues to the hiccup mystery. The study included 13 infants, including some preemies, in the first few weeks of life. Electrodes were attached to their scalps as part of an EEG in order to record brain waves. Another electrode was attached to their torso to record hiccups. When babies hiccupped, the diaphragm contracted, and the EEG was able to record a change in their brain waves. Sensory signals were activated in the infants’ sensory cortices with each hiccup.

The signals create a pathway that teaches the brain how the diaphragm works. The more the pathway is used, the stronger that pathway becomes. The authors suggest that hiccups may help teach babies to breathe by giving information to their developing brains, which also helps explain why hiccups begin very early in gestation. So why do adults still hiccup? Their theory is that hiccups are just a left over process from infancy that we don’t really need any longer.