9 months baby sleep head sweat, may be due to physiological factors, may also be due to rickets, hyperthyroidism and other pathological factors. 1. Physiological factors: such as indoor temperature is too high, covering clothing is too thick, as well as their own metabolism, etc., will lead to the production of too much, so it is possible to cause the baby’s head to sweat after sleeping. 2. Pathologic factors: such as rickets, hyperthyroidism and so on. (1) rickets: it is one of the most common chronic diseases during the growth and development period of children, and it is more likely that 9-month-old babies are considered to be vitamin D-deficient rickets. It will lead to increased sweating when the baby falls asleep, and may also be accompanied by problems such as night terrors. (2) Hyperthyroidism: also known as hyperthyroidism; although the incidence is less likely because of metabolic abnormalities, it can also lead to increased sweating after the child falls asleep. Nine-month-old baby sleep head sweat, it is recommended to go to the hospital pediatrics examination; identify the cause, under the guidance of the doctor to take reasonable measures to avoid affecting the normal development of the child.