Ah, meconium. The scientific name for the tarry, sludgy, blackish, greenish bowel movements that your baby graces you with in his or her first few days of life. Luckily, meconium doesn't smell half as bad as it looks. That's because your baby's intestines are clean as a whistle and haven't colonized with bacteria yet when they join you in their bright new world. Though most parents know that your baby should pass their first meconium within 24 hours of entering the world, some of you are probably wondering, when will my kid stop pooping meconium? After all, just because it doesn't stink doesn't mean it's not a sticky mess.
Because your baby's first bowel movement doesn't contain breast milk or formula just yet, it's packed with the materials your baby ingested in utero, according to Parents. From skin cells, to mucus, to amniotic fluid, to bile, to water, it's no wonder their meconium is viscous and sticky as all get out. But it won't stay that way forever. According to What To Expect, your baby's bowel movements move away from meconium two days after they've been born, and start heading toward a transitional state of stools. Transitional stools will be more green and less tacky and tarry than meconium. Translation — your baby's intestinal tract is moving and grooving. Depending on what you're feeding your baby, your baby's poop will take on a different color and consistency.
Healthy Children noted that breastfed babies will start passing poop that usually looks a little bit like dijon mustard — yellowish in tone, slightly watery, and seedy looking bits. Formula fed babies usually have stool that's thicker in consistency, more like a paste, and yellow or tan in color. If you're concerned with color, keep in mind that earth tones are generally a good sign. The transition to milk stools should be complete around day six or seven, according to Very Well. And if your baby is still passing meconium after four days, or if your baby's stool hasn't fully transitioned into milk stool after six days, it can be a sign that your baby's not getting enough nutrition.
If your baby doesn't pass meconium in their first 24 hours, or if your baby doesn't move on from meconium within a few days, you'll want to contact your doctor. Babies who don't pass meconium may have intestinal obstructions, and babies who haven't moved on from meconium may need extra attention from a healthcare professional.