Stool colors & patterns in infants: What's normal & when should you worry?

Help! My baby is constipated. She hasn't pooped for days.

We hear versions of this all the time.

Constipation isn't defined by how often babies have a bowel movement. A breastfed baby might have a bowel movement every time he eats (and in between) or he might go less than once a week. (Watch out when it finally comes - it often escapes the diaper!) Most formula fed babies have a bowel movement 1-3 times a day. Babies who get some breast milk and some formula can have characteristics of each feeding type.

During the first few days of life the stool looks black and is thick. This is called meconium. It occurs in both breast fed and formula fed babies. If your baby doesn't have meconium within 24 hours of birth an evaluation to decide if there's a problem should be done. Be sure to talk with your baby's doctor if he doesn't poop within 24 hours of birth or if the meconium is formed like a plug. (See a photo on Stanford's newborn page.)

Meconium stool. Photo by Azoreg via Wikimedia Commons

After the first few days there is a period of transition stool. The stools become more green and sticky. This is the meconium mixed with breastmilk or formula stools. It happens earlier in formula babies and after mother's milk comes in for breast fed babies.

After the transitional stools, the stools will vary in color and consistency depending on if the baby gets breastmilk or formula. If breastmilk is the primary food, the stools can vary quite a bit. They often look like yellow cottage cheese, with a lot of liquid and chunks. It often becomes a bit thicker (like pudding) as a baby gets older. It is not diarrhea just because it is watery. Breast fed stools can vary in shades of yellow to brown or green, often changing depending on what the mother ate. Bright green and frothy stools can indicate a low fat diet in a breast fed baby. The fore milk has less fat than the hind milk, so if the baby consistently has frothy bright green stools we will monitor the baby's weight closely to ensure adequate growth and evaluate the amount of milk the mother is producing and baby is drinking.

If a baby is taking formula, the stools can look shades of yellow and brown and be the consistency of peanut butter, pudding, or thick oatmeal. Formula fed stools tend to smell more foul than breast milk stools, but even breast fed baby poops can stink.

Once a baby eats solids (or pureed foods) the stools can thicken a bit but should never be hard. They usually become more foul smelling at this time. Sometimes chunks of food (especially carrots, corn, and raisins) can be seen in the stool. This is normal.

If a baby takes an iron supplement the stools might turn dark green or black. This is normal and not a concern. This does not happen from the amount of iron in baby formula. All formula should have iron. It is an important nutrient for all babies and low iron formula is not recommended.

What's important?

• A term baby should gain about 15-30 grams per day after the first week of life.
• Blood in the stool can be from swallowed blood (often from a crack in mother's nipple), constipation, food allergy (usually cow's milk protein), or infection and should be evaluated.
• It is normal to have different shades of yellow, brown, and green stools.
• A baby with a swollen (distended) abdomen and discomfort or a change in feeding patterns should be examined.
• A baby should not have formed stools as long as they are on primarily breast milk or formula.
• Poop should never be a shade of white (liver concerns), red (blood), or black -if not on iron supplements (digested blood).
• Mucus in stool could be simply swallowed mucus but can be a sign of infection or food allergy.