Yes, it is common for unborn babies to have hiccups during the third trimester of pregnancy. Hiccups occur when the baby's diaphragm contracts involuntarily. This can be felt as rhythmic movements or flutters in the mother's belly. Hiccups are a normal part of fetal development and are not usually a cause for concern. They may occur more frequently after meals or when the baby is active. If you notice excessive or prolonged hiccups, it is always best to consult with your healthcare provider for reassurance and guidance.