Meconium: All about your baby’s first poo, the changes in colour and when to worry

(Image: Getty Images)

Many parents are shocked at their newborn’s first poo.

I’m Dr Daniel Golshevsky, but many know me as “Dr Golly”. I wanted to share a chapter from my very first book with you, Your Baby Doesn’t Come with a Book.

As a paediatrician, I’ve been working to support the happy and healthy development of families for over a decade, but also, I’m a dad and most certainly understand the joys as well as the challenges that come with being a parent! I hope my knowledge and experience can empower your parenthood journey.

Newborn baby nappy change and their first meconium poo — Meconium is a thick and sticky tar-like substance, usually dark green or black. *(Image: Getty Images)*

All about meconium, your baby’s first poo

Many parents get a real shock when they see their baby’s first poo, because it rarely looks like what they expect. It’s a thick and sticky tar-like substance called meconium, usually dark green or black, and completely odourless. It usually occurs within the first 24 hours of life.

Occasionally, babies will pass this while still in utero, or during the delivery process. If your baby passes meconium before being born, there is a risk that their first breath will actually bring some of this into their lungs. Meconium is harmful to newborn lung tissue, so if your baby is born with meconium-stained waters, they will be observed closely for 1–2 days to ensure no meconium entered the lungs.

Changes in poo colour

The meconium slowly transitions to different types of poo, which can range from yellow to brown to green, and everything in between. There is a big range of normal, but this transition usually occurs within the first week of life.

Baby's first poo and what the colour of the poo means — Meconium slowly transitions to different types of poo, which can range in colour. *(Image: Dr Golly)*

Pasty light brown: Normal poo for babies having formula, a peanut butter consistency.

Mucus in poo: This poo looks snotty or like shiny string. This can indicate an intolerance to something in a breastfeeding mother’s diet or the formula. See your doctor if your baby has mucus in their poo.

Black: This can be a sign that your baby has ingested some blood; it is not normal. See your doctor if your baby has black poo. Sometimes it is from cracked/bleeding nipples when breastfeeding. Meconium passed in the first few days is black (very dark green) but your baby’s poo should not stay black in colour.

Thick brown: Normal poo once solids begin, resembling more of an adult poo, stronger smell than when just on milk feeds.

Mustard yellow: Normal breastfed-baby poo, pasty or seedy. Breastfed babies can also have looser brown or green poo.

Red: This is not normal and could be a sign that your baby is bleeding. Can also be a sign that your baby has an intolerance. See your doctor if your baby’s poo is red.

White: This is not normal. This could be a sign that the liver may not be producing enough bile, making the poo white in appearance and with a chalky texture. See your doctor.

Dark green or greenish black: Meconium passed in the first few days. This is your baby’s first poo and is sticky and tar-like. It is a combination of amniotic fluid, bile and fatty acids that your baby ingested while still in the womb.

Light green: Normal formula-fed baby poo; it has simply passed through your baby’s gut faster.

Frothy: Frothy poo that burns the skin can be a sign of lactose overload (this is a different entity to lactose intolerance) and results from feeding too frequently. The foremilk in breastmilk is lactose-heavy so feeding too often causes excess lactose intake.

Illustration of baby's frothy poo and what it means — Frothy poo that burns the skin can be a sign of lactose overload. *(Image: Dr Golly)*

When to worry about poo

We don’t like to see stools that are white/pale, black (once the meconium has passed) or red; these babies need to be seen by a doctor.

Many parents have concerns regarding the frequency of their child’s bowel actions, and worry their child might be constipated. When concerned about constipation, you should look at the consistency of the poo, rather than the frequency with which it is passed.

Some babies will poo with every feed, others may only poo once a week. As long as the stool is soft and easily passed, you shouldn’t worry about how frequently your baby is pooing. Breastfed babies are almost never constipated.

Mucus or blood in the poo is a sign of intolerance (to breastmilk or formula), and should be reviewed by a doctor.