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Why does my newborn baby have black poop?!

Why does my newborn baby have black poop
Mother changing baby's first diaper/nappy full of black poop known as meconium. It can be hard to clean so make sure to use coconut oil after to help clean it easily.

Your baby’s first poop is called meconium. Meconium’s colour ranges from black to dark green and it will be a bit like tar – thick and sticky. This type of poop can shock first-time parents as it isn’t what they were expecting when they imagined changing dirty nappies.

What is meconium?

Meconium is made up of everything your baby has ingested during your pregnancy – lanugo, mucous, amniotic fluid, cells from skin/intestinal tract, bile and water. Despite meconium’s colour and appearance, it doesn’t smell like the baby poop that is to come! This is because your baby is brand new to the world, and their gut has yet to be colonised with bacteria.

Check out our video here for more!

What does meconium look like?

Meconium is black, tarry and sticky like this photo below.

When will my baby pass meconium?

Healthy, full-term babies should pass their first meconium poop within 24-48 hours after they are born – some pass it really quickly after birth. If you are still in hospital, the medical team caring for you and your baby will keep an eye on this, and if you’ve birthed at home or returned home soon after birth, generally your midwife or Dr will keep in touch about baby’s progress.

What does meconium poop look like
This is a nappy/diaper full of meconium, black tarry poop. It occurs the first 24-48 hours after birth.

If baby doesn’t pass meconium within 1-2 days, then it’s possible that there may be an issue such as intestinal obstruction, or other illness. If you are concerned about your baby’s poop, it is crucial to immediately contact your doctor or midwife. This is to ensure that there are no problems or complications.

How long does meconium last?

Meconium stools generally last around 3-5 days after your baby is born. After meconium, comes transitional stool which has more of a greeny/brown colour – this is the in-between poop while your body’s baby begins processing milk more efficiently.

After a day or two of transitional poop, you can expect that you baby will start to have regular baby poop – for breastfed babies, this can have a mustard colour and sometimes look like it has seeds  (fat globules) in it. For formula fed babies, the colour can range from brown/dark green/dark yellow – depending on the formula type.

What happens if baby passes meconium during labour or pregnancy?

Generally babies do not poop in the womb. However, sometimes they do pass meconium during labour which can cause a complication called meconium aspiration syndrome. This sometimes happens as a result of fetal distress.

What is Meconium Aspiration Syndrome?

Meconium aspiration syndrome is when babies breathe in amniotic fluid that contains meconium. The meconium particles can block a newborn’s airways and cause parts of their lungs to collapse. This is a serious condition – although the outlook is generally optimistic.

Meconium aspiration treatment requires swift action that may include suctioning of upper airways, supplemental oxygen or antibiotics. Your baby will generally need to spend at least a couple of days in a Neonatal Intensive Care Unit (NICU) or Special Care Unit for monitoring.

Does meconium smell bad?

No, meconium does not have a strong odor. It is actually odorless, which can be a relief for new parents who may be worried about unpleasant smells.

Since the baby has not started digesting breast milk or formula yet, the poop does not have a distinct smell.

However, as your baby’s diet changes and they begin to consume breast milk or formula, their poop will start to develop a more noticeable odor. This is completely normal and nothing to be concerned about. It’s just a sign that their digestive system is maturing and functioning as it should. So, for now, enjoy the lack of odor while it lasts!

So – is it normal?

In general – yes! If your baby is under 3 days old, meconium poop is expected and very normal.

My hot tip to wipe off this sticky tar poop easier – lather coconut oil on your baby’s bottom during changes. It’ll help it wipe right off clean next time baby produces one of these poops. Don’t forget to reapply the coconut oil after wiping!

Wanna know more about your baby’s poop?
Check out our poop guide guide here. 

It’s important to note this blog is general education only. For any personal based advice regarding you or your baby please seek advice from your own healthcare professional.

  1. Goel, A., & Nangia, S. (2017). Meconium aspiration syndrome: challenges and solutions. Research and Reports in NeonatologyVolume 7, 19–28.
  2. Monfredini, C., Cavallin, F., Villani, P., Paterlini, G., Allais, B., & Trevisanuto, D. (2021). Meconium Aspiration Syndrome: A narrative review. Children (Basel)8(3), 230.
  3. Poos and wees. (2023, July 4). Raising Children Network.
  4. Skelly CL, Zulfiqar H, Sankararaman S. Meconium. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: