The very first stool your baby passes doesn’t smell bad. That’s because the black, tarry-looking stuff, called meconium, is sterile. Until the intestines are colonized with bacteria, there’s nothing to make poop stinky. Don’t go bragging about your baby’s odorless poop, however; bacterial colonization begins with the first feeding. Some babies will actually pass meconium while still in the uterus, usually as a result of physiologic stress like an infection or a difficult delivery. When this occurs, the baby is at risk for lung disease, called meconium aspiration syndrome. Your newborn will most likely have his first bowel movement sometime in the first 24 hours of life. When stooling takes longer than this, doctors look for problems such as intestinal blockages, an underdeveloped anus, or stool that is stuck, called a meconium plug.
Your newborn will continue to pass meconium over the first day or so, but if he is feeding well you’ll notice that over a few days the stool goes from black to dark green to yellow in color. Breastfed babies usually pass poop that looks like Dijon mustard, watery with little whitish seedy-looking bits. Formula-fed babies may have less watery stool, usually pasty in consistency and yellow or tan in color. Many parents get concerned if they see the stool is green rather than yellow. In truth, all earth tones are fine, from yellow to green to brown.
When to Call the Doctor
There is 2 colors stool should not be. One is white. Stools the color of clay can be a sign of serious liver disease. The other is red. While blood in a baby’s stool may simply have been swallowed at delivery or may result from mom’s nipples bleeding, it’s always wise to have a doctor check the baby out.
- Author: David L. Hill, MD, FAAP
- Last Updated11/21/2015
Dad to Dad: Parenting Like a Pro (Copyright © American Academy of Pediatrics 2012)