Why Do Infants Get The Hiccups? Science Explained

Hiccups in newborns and young infants are so common that most parents barely blink at them. The diaphragm, the dome-shaped muscle below the lungs, suddenly contracts on its own. That quick spasm pulls air in, and the vocal cords snap shut a split second later, producing the classic “hic” sound. For infants, this reflex is not a sign of trouble. It is a normal part of early development, often triggered by feeding, swallowed air, or a still-maturing nervous system.

What Actually Causes the Hiccup Reflex in Babies?

The hiccup reflex starts in the brainstem, the oldest part of the brain. Nerves send a signal down the phrenic nerve, which controls the diaphragm. When that signal fires unexpectedly, the diaphragm jerks downward. The glottis, the opening between the vocal cords, closes almost immediately. That closure is what makes the sound.

In adults, hiccups are often linked to eating too fast, drinking carbonated beverages, or sudden excitement. In infants, the triggers are simpler and more frequent. A full stomach pressing against the diaphragm is a common cause. Swallowing air during a feed can do the same. Even a sudden change in stomach temperature, like moving from a warm bottle to a cooler room, can set off the reflex.

There is also a developmental angle. The nervous system of a newborn is still learning to coordinate signals. The pathways that normally suppress hiccups are not fully mature. This means the reflex fires more easily and more often than it will later in life.

Why Do Infants Get The Hiccups So Much More Than Adults?

Frequency is the key difference. Some infants hiccup several times a day, every day, for months. Adults rarely hiccup more than a few times a year. The reason is partly anatomical and partly neurological.

An infant’s stomach is small and sits high in the abdomen. It does not take much milk to fill it. A full stomach pushes upward on the diaphragm, which is already positioned more horizontally in babies than in older children and adults. That position makes the muscle more sensitive to pressure and stretch.

The neurological side matters just as much. The vagus nerve and the phrenic nerve carry signals between the brain and the diaphragm. In a newborn, the insulation around these nerves, called myelin, is still forming. Signal transmission is slower and less precise. The brain’s inhibitory circuits, the ones that stop a hiccup before it starts, are also underdeveloped. The result is a reflex that triggers easily and runs its course without much interference.

Some researchers have proposed that frequent hiccups in infants are not just a side effect of development but possibly a functional part of it. Brain scans and breathing studies have suggested that the rhythmic contraction of the diaphragm may help coordinate the neural circuits involved in breathing. This remains a hypothesis, not a proven function. What is clear is that frequent hiccups in a healthy infant are not a cause for concern.

Do Hiccups Hurt Babies or Disturb Their Breathing?

Hiccups do not hurt infants. A baby may startle at the first hiccup, but there is no evidence that the reflex causes pain or distress. Many babies continue feeding, sleeping, or looking around without interruption during a bout of hiccups.

Breathing is not compromised. The hiccup is a brief, involuntary spasm followed by normal breaths. Oxygen levels do not drop. Heart rate does not change. The reflex is self-limiting and does not interfere with the baby’s ability to breathe effectively.

One point worth noting: hiccups are sometimes mistaken for other infant behaviors. A baby who is gagging, coughing, or arching the back during or after feeding may have reflux, not hiccups. Reflux involves stomach contents moving back up the esophagus. Hiccups involve only the diaphragm and vocal cords. They are different mechanisms with different implications.

Why Do Hiccups Happen During or Right After Feeding?

Feeding is the most common trigger for infant hiccups. Several factors come together during a feed.

First, the stomach fills quickly, especially in a newborn. The expanding stomach pushes against the diaphragm from below. That mechanical pressure is a direct stimulus for the reflex.

Second, infants swallow air while feeding. This is true for both breastfed and bottle-fed babies, though bottle-fed babies may swallow more air if the nipple flow is too fast or too slow. The air collects in the stomach, adding to the pressure.

Third, the act of sucking and swallowing is itself a coordinated movement involving the diaphragm. The diaphragm normally moves downward during inhalation. During feeding, the baby coordinates sucking, swallowing, and breathing in a rapid sequence. That coordination is not perfect in a newborn. Small missteps in timing can trigger a diaphragmatic spasm.

There is also a temperature component. Cold milk or formula entering a warm stomach can cause a sudden change in stomach wall tension. Some clinicians suggest this may stimulate the vagus nerve, which runs from the brain to the abdomen and passes near the diaphragm. The evidence for this specific trigger is limited, but it is a commonly observed pattern in practice.

How Long Do Infant Hiccups Last and When Do They Stop?

Most infant hiccups last between 5 and 15 minutes. Some bouts are shorter, some longer. In nearly all cases, they stop on their own without any intervention.

The frequency of hiccups tends to peak in the first few months of life. As the nervous system matures and the stomach grows, the episodes become less frequent. Most infants outgrow daily hiccups by the time they are 6 to 12 months old. Some babies stop much earlier. Others continue to hiccup occasionally well into toddlerhood, which is also normal.

There is no evidence that the frequency of hiccups in infancy predicts anything about future health. Babies who hiccup several times a day are not more likely to have reflux, breathing problems, or neurological conditions than babies who rarely hiccup.

What Should Parents Do When a Baby Has Hiccups?

In most cases, the answer is nothing. Hiccups resolve on their own. Intervening is not necessary and some common home remedies are not appropriate for infants.

If the hiccups occur during a feed, pausing for a minute can help. A gentle burp may release trapped air and reduce pressure on the diaphragm. Holding the baby upright for a few minutes after feeding can also help, especially if the hiccups are linked to a full stomach.

If the hiccups start between feeds, a pacifier or a few sips of warm water can sometimes interrupt the reflex. These methods work by shifting the baby’s attention or altering the rhythm of breathing. They do not always work, and that is fine. The hiccups will stop regardless.

There are several things parents should not do. Do not startle the baby. Do not pull on the tongue. Do not press on the soft spot of the skull. Do not give gripe water or any herbal remedy specifically to stop hiccups. These methods are not supported by evidence and some carry unnecessary risks. Gripe water, for example, is not regulated as a medication and its ingredients vary widely by brand.

The only time hiccups warrant a medical call is if they are accompanied by other symptoms. Persistent hiccups that last for hours, hiccups with vomiting, hiccups with a fever, or hiccups that seem to cause genuine distress are reasons to contact a pediatrician. Isolated hiccups, no matter how frequent, are not.

Could Hiccups Be a Sign of a Medical Problem?

In rare cases, frequent hiccups can be linked to an underlying condition. This is the exception, not the rule.

Gastroesophageal reflux disease, or GERD, is the condition most commonly mentioned in connection with infant hiccups. GERD involves stomach acid moving up into the esophagus. It can cause hiccups, but it also causes other symptoms: frequent spitting up, arching of the back during feeds, irritability, poor weight gain, and coughing. Hiccups alone are not a sign of GERD.

Neurological conditions can also cause hiccups, but these are rare in infants and almost always present with other signs, such as seizures, abnormal muscle tone, or developmental delays. Hiccups alone do not suggest a neurological problem.

Medications, electrolyte imbalances, and infections can trigger hiccups in people of any age. In infants, these causes are uncommon and would come with other symptoms. A healthy baby who eats well, gains weight, and hiccups frequently is not showing signs of disease.