It is normal for newborns to have hiccups. A thin layer of muscle called the diaphragm is located between the baby’s thoracic and abdominal cavities, separating the thoracic and abdominal cavities. The diaphragm is part of the baby’s respiratory muscles. When the diaphragm contracts, the chest cavity expands, causing inhalation, while when the diaphragm relaxes, the chest cavity volume decreases, causing exhalation. When a baby eats milk too quickly, eats too much milk, or inhales cold air, the plant nerves are stimulated and the diaphragm suddenly contracts, causing rapid inhalation and a “burp” sound. When there is a rhythmic burping sound, the baby has hiccups. When your baby has hiccups, parents can hold your baby upright and pat his or her back to expel the air in the stomach, or give him or her some warm water in small amounts to effectively improve the hiccups.