The first type of stool your newborn will have is called meconium. It is dark green in color, and a thick, sticky consistency (a little thicker than jelly). Some babies will pass meconium in utero; this is more common in babies who are born after their due date. Most babies will start having meconium stools in the first 48 hours of life. They typically last for a day or two, before turning into soft, yellow-green transitional stool.
During the first few weeks, your baby’s stool should become mustard-yellow with light seedy pieces in it. The consistency is thin but not liquid, similar to that of mustard.
Over the first few months, the yellow seedy stool will gradually become slightly firmer, more uniform in consistency, and more brownish in color. For the first 4-6 months (before baby eats solid foods), each stool should be about the consistency of toothpaste.
Newborns will poop approximately once each time they eat, or about 8-12 times per day. Formula-fed babies will typically have smelly stools, while breastfed babies typically have stools that do not smell very much at all.
These colors are all normal for stool, and the color usually changes in this order: