Patient's question:
NoDoctor's answer:
Spitting up is a common phenomenon in infants and is caused by two main reasons: first, it can be a symptom of systemic or gastrointestinal diseases; second, the anatomical and physiological characteristics of an infant's gastrointestinal tract make it prone to spitting up. Overall, spitting up caused by the second reason is more common.The stomach of a newborn, when viewed from the front, lies horizontally in an unstable position. Additionally, the cardiac sphincter (the entrance to the stomach) is relatively loose. That is to say, when adults eat, after food enters the stomach, the cardiac sphincter contracts to prevent the food from flowing back into the esophagus. However, since the cardiac sphincter of an infant cannot contract effectively, milk and other substances entering the stomach can more easily flow back into the esophagus.
Moreover, compared to adults, the larynx of a newborn is positioned higher, and their clumsy way of sucking on the nipple makes it easier for air to be inhaled along with the milk into the stomach. Therefore, when the child burps or moves around, the milk ingested is more likely to be spit up.