Eight or nine months of the baby sleeps less than 10 hours a day, if there are no other adverse symptoms, generally do not need special treatment; if also accompanied by excessive sweating, occipital baldness and other conditions may be related to calcium deficiency, the need for timely calcium supplementation. 1. If the milk, mental state are normal, parents do not need special treatment. Eight or nine months of the baby only sleep less than 10 hours a day most of the normal phenomenon, the baby generally in the first three months when the sleep time may reach 15 hours to 22 hours or so, later with the age of the month, the sleep time will gradually decrease. 2. If the baby sleeps less than 10 hours a day, and accompanied by night terrors, restless sleep, excessive sweating, occipital baldness and other phenomena, you need to go to the hospital for a trace element examination, to determine the need for calcium deficiency in a timely manner to supplement calcium treatment. Eight or nine months of the baby only sleep less than 10 hours a day, there may be other reasons, need to observe the baby, if necessary, go to the hospital for examination.