Just after breastfeeding on the spit may be too fast feeding, maternal nipple inversion and other physiological factors, or to consider is congenital hypertrophic pyloric stenosis, dyspepsia and other diseases caused by. 1. physiological factors: due to the baby’s central development is not yet perfect, poor coordination of swallowing muscle groups, if the breastfeeding speed is too fast, maternal nipple inversion, will lead to the baby to inhale a lot of air, appeared to spit up just after breastfeeding. 2. Congenital hypertrophic pyloric stenosis: Congenital hypertrophic pyloric stenosis may be caused by heredity, hormonal disorders of the digestive tract and other factors. The child will vomit, mostly after breastfeeding, and the vomit is milk or milk clot. It can appear 2-3 weeks after birth and as late as 5 months of age. 3. Dyspepsia: Dyspepsia may be caused by Helicobacter pylori infection, heredity, gastrointestinal dyskinesia and other factors. The child will have postprandial fullness accompanied by spitting up. There may be other reasons for spitting up after breastfeeding. It is recommended that you go to the hospital in time for a complete examination to determine the cause of the problem, and then give targeted treatment under the guidance of the doctor.