Newborn babies who don’t poop but only pee can be caused by insufficient milk intake, constipation, intestinal obstruction, and so on. 1. Insufficient milk intake: If the newborn is not fed enough, such as insufficient breastfeeding or insufficient formula feeding, too little stool formation will not poop phenomenon, but because of normal renal function, it will be normal urination. 2. Constipation: mostly seen in formula-fed newborns, mainly because of too little water added, resulting in the formation of dry stool constipation phenomenon. 3. Intestinal obstruction: may be caused by congenital megacolon, which will lead to stool can not be discharged, only the phenomenon of urine. Newborn babies do not poop only pee, there may be other causes, such as congenital anal atresia, if the symptoms continue to be unrelieved, you should consult a doctor to find out the cause.