Why is my baby vomiting?

Vomiting happens occasionally when a baby overfeeds. It is more common when mothers have a large milk supply or when a baby is overfed with a bottle. Vomiting produces more milk than spitting. The milk shoots out of the mouth and goes quite a distance, and the baby may be unhappy for a few minutes. Danger signs include a baby who has a sudden change in feeding pattern or who suddenly starts vomiting more than twice a week, has a fever or diarrhea, vomits yellow, green, or bloody milk, or has black or red blood in the stool (poop). These may indicate an infection, major allergic reactions, or other serious problems.

A) The process of vomiting

Vomiting is a complicated, coordinated process that involves the abdominal muscles, small bowel, stomach, swallowing tube (esophagus), associated valves, and the closing of part of the throat to protect the lungs. If your baby is vomiting, you may:

  • See the chin up and head forward in a sniffing position.
  • Hear a retching sound or the baby hold its breath.
  • See the baby bring up a large amount of milk.
  • See the milk shoot out of the mouth and go quite a distance.
  • Find the baby is unhappy for a few minutes after vomiting.

B) Healthy babies who vomit

Normal babies may vomit twice a week.

Vomiting happens occasionally when the baby overfeeds. Vomiting is more common when mothers have a large milk supply or when a baby is overfed with bottled milk. Vomiting can also be brought on when the baby is burped when sitting on the mother’s lap instead of placed against her chest and shoulder.  

Normal babies in this situation will be generally content when not vomiting and will grow well.

Vomiting is not the same as spitting and there are ways to tell the two apart.

C) When vomiting is abnormal

1) Signs of a problem

If your baby starts vomiting more than twice a week, please see your health-care providers.

Other danger signs include a baby who:

  • Is suddenly very unhappy or sleepy.
  • Has a sudden change in feeding pattern from normal to much more frequent or much less frequent feeding.
  • Does not grow well.
  • Has a fever or diarrhea.
  • Vomits forcefully and frequently.
  • Vomits at night.
  • Vomits with a yellow, green, bloody, or black colour.
  • Has blood in the stool (poop).
  • Starts vomiting after six months of age.

2) Causes of abnormal vomiting

There are many causes of abnormal vomiting, including:

  • Viral infections
  • Bacterial infections:
    • Bladder
    • Ear
    • Meningitis
    • Pneumonia
    • Appendicitis
    • Kidney
  • Blockages of the gut:
    • Blockage of the exit of the stomach (pyloric stenosis)
    • Rotation (volvulus) or narrowing of the gut
    • Telescoping of the gut into itself (intussusception)
  • Severe allergies
  • Brain tumours
  • Increased pressure in the brain
  • Genetic abnormalities
  • Poisoning

3) Blood in the vomit

As digested blood turns black, vomit that contains blood can be red, black, or contain black flecks. Causes include: 

  • Wounds in the swallowing tube (esophagus) or stomach
  • Bleeding disorders such as low vitamin K levels
  • Anatomic abnormalities
  • Tumours
  • Swallowing blood during delivery
  • Blood taken in when breastfeeding