Five and a half months baby frequent night waking, may be related to physiological factors, may also be due to vitamin D deficiency rickets, gastrointestinal dysfunction and other causes. 1. Physiological factors: five and a half months of the baby if the temperature is too high, the environment is noisy sleep environment, easy to lead to physical discomfort, the phenomenon of frequent night waking may occur. 2. Vitamin D deficiency rickets: five and a half months of the baby if parents did not pay attention to the reasonable supplementation of vitamin D, resulting in a serious lack of vitamin D, it is likely to induce vitamin D deficiency rickets, resulting in increased neural excitability, which may result in frequent night awakenings, but also can be accompanied by occipital baldness, head sweating and other manifestations. 3. Gastrointestinal disorders: 5 months and a half of the baby’s gastrointestinal system development is immature, if parents feed improperly, such as frequent breastfeeding, or one-time feeding too much milk, resulting in indigestion, resulting in gastrointestinal dysfunction, easy to cause abdominal distension and discomfort, may show frequent night waking. Five and a half month baby frequent night waking, may also be other causes, if accompanied by obvious discomfort, it is recommended to seek medical attention as soon as possible, to give targeted treatment.