To read the previous section of this entry, please read Constipation in Babies.
Changes in stool as your baby develops depends on their age.
A Newborn
As you probably know, after birth a newborn will evacuate meconium, a forest-green, thick, sticky substance that accumulated in their intestine in utero. The evacuation of meconium will take place over a couple of days, with about 3-4 stools a day. They won’t necessarily be abundant each time. The colour of the stool will shift from forest green to lime green to a mustard yellow with lumps and will become more and more liquid.
At this point, your baby’s stool characteristics and frequency are associated with what they drink.
To read about the different types of colour, read my article Stool in a Young Baby.
A Baby up to 6 Weeks
Up to about 6 weeks, a baby doesn’t know how to push out gas and stool. You will see their face turn red as they try to push. Alternatively, they might become rigid due to their discomfort. They’re learning how to evacuate the contents of their intestine themselves (pushing at the right spot). This doesn’t mean they’re constipated. They’re simply learning.
Their immaturity means that the pushing effort isn’t always easy. Often the baby will pass stool while breastfeeding. This is because they’re focusing their efforts on feeding and relax the rest of their body. This facilitates the passing of stool. You should know that a young baby with discomfort in their abdomen, bloated or have gas or stool to be evacuated will associate breastfeeding with comfort.
Remember that everything new entering their mouth will bring changes to what comes out and ends up in the diaper—colour, quantity, frequency, smell, etc.
If a mother breastfeeds but also gives their baby formula, if a baby is taking medication (ex.: antibiotics), if your 5-month-old child is starting to eat, you will see differences.
Stool in a Baby Breastfed Exclusively
A baby exclusively fed with their mother’s milk will pass several formless stools a day. They may be lumpy (with small particles) or pasty (with mucus or secretions in them, stickier). This is normal. If you see mucus and/or blood in your baby’s stool, this doesn’t automatically mean that your baby has an intolerance or allergy to your milk. Make sure the baby gets enough milk, as a reduced flow to the baby’s mouth when breastfeeding can cause this symptom if the amount of milk diminishes. Increase the number of feedings and see if the blood disappears and you’ll have your answer.
A breastfed baby will rarely be constipated, as breast milk is a laxative. Also, given breast milk is easier to digest, the intestine, even in a young baby, will absorb an increased amount of milk to build up fat reserves.
There’s no waste in breast milk. What we find in the baby’s diaper is what the baby didn’t have time to absorb via their intestines. This is why after 4-6 weeks of life, a baby may not pass stool for several days or even a week. Yet they aren’t constipated.
You should know, however, that a baby should frequently urinate throughout the day. This is associated with them meeting their daily liquid requirements and preventing dehydration.
Stool in a Bottle-fed Baby
A bottle-fed baby can’t skip passing stool for more than 2-3 days. They need to evacuate waste that can’t be digested. Also, if their stool is soft or pasty, the baby isn’t constipated. If it’s hard and dry and difficult to evacuate, your health professional should check to see if the milk formula is right for your baby.
You should also know that milk formulas with iron don’t cause constipation. Instead, it’s a reaction to the milk itself that produces this type of symptom.
A Baby After 6 Weeks
After 6 weeks, the baby will develop their own stool pace.
Each baby is different.
Some babies will have slower intestinal transit, while others faster.
To better understand the signs of constipation in your baby, read The Symptoms of a True Constipation Problem in a Newborn (in french).
