Baby constipation 101: Symptoms, causes, and how to help a constipated baby

By: Dahlia Rimmon MS, RDN

Medically reviewed by: Lauren Mahesri, RDN

When your baby is constipated, everyone feels it. Your baby is fussy and uncomfortable, the whole house is running on zero sleep, and you're up at midnight Googling remedies like it's your new part-time job. Not to mention, every diaper change feels like a high-stakes, edge-of-your-seat situation.

To help, we're breaking down everything you need to know about baby constipation, including the most common symptoms, reasons why it happens, and simple strategies to keep things moving again. We'll also explore how your baby's gut health plays a role in why things get backed up in the first place.

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What is baby constipation?

Babies have developing digestive systems, so variations in bowel movements are completely normal. In fact, every baby has their own unique pooping rhythm—some go once a day, others go several times a day, and some babies go every couple of days. Their pattern can shift depending on whether they're breastfed, formula-fed, combo-fed, or starting solid foods. Because there's such a wide range of what's considered "normal," it can be confusing to know when your baby is truly constipated.

Signs and symptoms to look for

True baby constipation occurs when your baby has:

• Poop that is difficult and/or painful to pass

• Infrequent poops (fewer than two per week)

• Hard, pellet-like poops

Along with changes in their stool, constipated babies may also:

• Be incredibly fussy and uncomfortable

• Spit up more than usual

• Shows signs of abdominal pain or discomfort

• Have bloody streaks in their stools

It's also helpful to know what doesn't count as constipation. Babies are still learning how to coordinate their muscles, so grunting, turning red, or making funny faces while pooping is completely normal. Straining is common too. Babies are still learning to coordinate the muscles around their anus, after keeping them tightly closed for nine months. Plus, lying on their backs doesn't give them much help from gravity. Straining only becomes a concern if it lasts longer than 10 minutes or seems very painful.

What causes constipation in babies?

There are several reasons why your baby might experience constipation. Some are temporary, while others are related to feeding, diet, or what's happening inside their developing digestive system.

Feeding changes

Any big feeding change, like switching formula brands or transitioning from breast milk to formula can temporarily slow things down. Formula is generally harder to digest than breast milk, so some babies experience constipation during the adjustment period. "The proteins in breast milk are easier to break down and digest compared to cow's milk formula," says Danielle Zold, RD, LDN, CLC, CGN, Pediatric Registered Dietitian and Founder of Nourished Pediatrics. "Breast milk moves through the digestive system faster than formula, which typically means easier digestion and more frequent bowel movements in the early weeks or months."

Zold explains that breastmilk also contains its own digestive enzymes (amylase, lipase, protease) that helps babies break down macronutrients. Formula doesn't contain these enzymes, which can initially make it a bit tougher on little tummies.

Milk type

Both breastfed and formula-fed babies can have healthy digestion, and occasional constipation usually resolves as their baby's digestive system matures. "On average, formula-fed infants have firmer, less frequent stools than breastfed infants, which can make constipation more likely," says Zold.

That said, not every formula-fed baby will become constipated, and some exclusively breastfed babies may experience constipation for other reasons, such as allergies, gut dysbiosis, or functional constipation. Every baby is different, and what's normal can vary widely from one baby to the next.

Incorrect formula preparation

If your baby drinks formula, it's important to follow the exact water-to-powder ratio on the label. Incorrectly preparing your baby's formula may lead to dehydration, which makes stools harder and more difficult to pass.

Low fiber diet

Once your baby starts solid foods, their diet plays a bigger role in digestion. It's common for babies to experience a little constipation early on as their digestive system adapts to solid foods. If their meals don't include enough fiber-rich foods, they're more likely to get backed up. Helpful high-fiber foods for babies include fruits (especially "p" fruits like prunes, plums, peaches, and pears), vegetables, whole grains, and legumes.

Medical issues

Certain medications, as well as some underlying medical or anatomical conditions, can contribute to constipation. These are less common but worth discussing with your pediatrician if poop problems are ongoing.

Gut dysbiosis

Your baby's gut is home to trillions of tiny microorganisms (also known as the gut microbiome) that play a significant role in digestion and overall health. "Gut bacteria are important for helping digestion, they support the immune system, and keep the gut lining healthy," says Zold. Gut dysbiosis occurs when your baby's gut microbiome is disrupted, causing an imbalance between "good" and "bad" bacteria.

Zold explains that certain types of bacteria, like Methanobrevibacter Smithii, produce excess methane which can slow motility. When this happens, your baby's digestive system struggles to function normally, often leading to uncomfortable digestive symptoms, like constipation. "There can be overgrowth of these types of bacteria due to many factors, like c-section delivery and little to no intake of probiotic-rich foods or supplements," says Zold.

Home remedies to relieve constipation in babies

There are several gentle and effective ways to support healthy bowel movements at home. Here's how to relieve constipation in babies quickly:

Gentle movement

Encouraging movement can help stimulate the muscles involved in bowel movements, making it easier for babies to pass stool. Try these simple techniques:

• Tummy massage: Gently massage your baby's belly in a clockwise motion, following the path of their intestines, to stimulate digestion and stimulate bowel movement.

• Bicycle legs: Move your baby's legs in a bicycle motion while they lie on their back. This helps release pressure in the abdomen and encourages bowel movements.

Warm bath

A warm bath can help relax your baby's abdominal muscles, making it easier for them to pass stool. Plus, it's a soothing way to comfort them when they're fussy.

Increase fiber-rich foods

Once your baby has started eating solids, adding fiber-rich foods can help soften stools and promote regularity. Some great baby-friendly options include:

• Pureed fruits like berries, peaches, pears, and prunes

• Mashed avocado

• Pureed sweet potato or broccoli

• Pureed beans or lentils

• Ground flaxseed or chia seeds (mixed into purees)

Consider a probiotic supplement

Probiotic supplements can support your baby's gut by adding beneficial bacteria and strengthening the intestinal lining to help keep harmful bacteria out and improving gut dysbiosis.

"Some probiotic strains can help with infant constipation, primarily by regulating the microbiota and influencing the nervous system and immune system," says Zold. Specific probiotic species that have been clinically studied to support the infant microbiome include Lactobacillus reuteri, Bifidobacterium infantis, and Bifidobacterium bifidum.

Probiotic supplements are not safe for babies who are premature or immunocompromised. Always talk to your pediatrician before starting any supplement.

Think about HMOs

Human milk oligosaccharides (HMOs) are carbohydrate-based prebiotics that nourish beneficial gut bacteria. Naturally found in breast milk, HMOs provide health benefits from infancy through adulthood, supporting immune function, brain development, and gut health. While evidence linking HMOs to constipation relief is lacking, research highlights their role in shaping the gut microbiome, specifically promoting a healthy gut environment and strong gut barrier.

NurtureBio was formulated by leading infant health and microbiome researchers to gently support your baby's developing gut. Our synbiotic combines targeted probiotic strains with HMO-inspired prebiotics to support a healthy, comfortable digestion routine. Always talk with your pediatrician before starting any new supplement.

Lactobacillus reuteri DSM 17938, which has the strongest evidence for improving bowel movement frequency.

That said, probiotics shouldn't be used as a standalone treatment for constipation. Based on current research, and guidance from major medical organizations, like the American Gastroenterological Association, there isn't enough evidence to recommend probiotics specifically to treat constipation in babies and children. If parents choose to offer a probiotic supplement, it's best to view it as a gentle, supportive option used alongside guidance from your pediatrician.