Newborn Runny Poop: What Are The Main Causes?

Diarrhoea in newborns is a common occurrence that can be caused by a variety of factors. The most common cause is a stomach bug virus, such as Rotavirus or Norovirus, which usually resolves within five to seven days. Diarrhoea can also be caused by immunisations, antibiotics, or a change in diet for the newborn or the mother, if breastfeeding. In rare cases, it can be a sign of a more serious condition, such as cystic fibrosis or a cow's milk allergy. It is important to monitor newborns with diarrhoea for signs of dehydration, which can occur quickly and be dangerous. If you notice any concerning symptoms, it is recommended to seek medical advice.

Viral, bacterial or parasitic infections

Viral Infections

Viruses are the most common cause of gastroenteritis, an inflammation of the digestive tract that results in vomiting and/or diarrhea. Rotavirus and Norovirus are the most common viruses causing gastroenteritis worldwide and in the United States, respectively. Other viruses that cause gastroenteritis include Astrovirus and Adenovirus.

Viral gastroenteritis is highly contagious and spreads through fecal-oral transmission, coughing, sneezing, and spitting. It can also be spread by contaminated objects such as toys or food. Symptoms of viral gastroenteritis include watery diarrhea, vomiting, abdominal cramps, fever, and headache.

Bacterial Infections

Bacterial infections are a less common cause of gastroenteritis. Bacteria that cause gastroenteritis include Clostridioides difficile (C. diff), Escherichia coli (E. coli), and Staphylococci. Salmonella and Listeria are less common causes.

Bacterial gastroenteritis is contracted by consuming contaminated food or water, touching contaminated surfaces or animals, or through person-to-person contact. It can cause fever and bloody diarrhea, and may lead to abdominal cramps.

Parasitic Infections

Parasitic infections that cause gastroenteritis include Giardia intestinalis and Cryptosporidium parvum. Parasitic infections are usually acquired by drinking contaminated water or through fecal-oral transmission, which is common in day care centers.

Parasitic gastroenteritis typically causes diarrhea that lasts for a long time and may come and go. It is usually not bloody. Children with parasitic infections may experience fatigue and weight loss.

Food allergies or medicine sensitivity

Food allergies and medicine sensitivity are common causes of runny poop in newborns. Here are some detailed explanations:

Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) is a common food sensitivity in babies, affecting up to 3% of infants in their first year. This allergy is caused by an immune system overreaction to the protein molecules in cow's milk. It can lead to allergic reactions in formula-fed babies and breastfed babies. In formula-fed infants, they may show an allergic reaction to their formula, while breastfed babies can react to cow's milk particles that leak into their bloodstream in small amounts after nursing.

Signs of CMPA in babies include:

• Blood or mucus in stools: The presence of blood or mucus in a newborn's stool is a key indicator of a possible milk allergy.
• Mucousy stool: Stools that resemble snot in the diaper can be a sign of a cow's milk protein allergy.
• Looser and mushier stool (diarrhea): If a baby experiences diarrhea two to four times a day for more than five to seven days, it could be a sign of CMPA. However, it's important to note that some healthy children also have loose stools.
• Other symptoms: Additional symptoms may include vomiting, rashes, hives, and swelling on the face.

Lactose Intolerance

Lactose intolerance is another condition that can cause runny poop in newborns. It is caused by the body's inability to absorb lactose, the sugar found in milk. This condition usually appears in older children, typically around the age of four or five. However, it can also affect newborns in rare cases.

Symptoms of lactose intolerance include:

• Gas: Babies with lactose intolerance often experience excessive gas.
• Loose stools: In addition to runny poop, babies may have multiple watery stools per day, ranging from mild to severe.
• Stomach bloating: Abdominal pain and bloating are common symptoms of lactose intolerance.

Antibiotic Use

The use of antibiotics can also lead to runny poop in newborns. Antibiotics can cause mild diarrhea, but this is typically not an allergic reaction. It is important to continue giving the prescribed antibiotic to your baby and consult your doctor if any serious symptoms occur.

Other Medicine Sensitivities

In addition to antibiotics, sensitivities or allergic reactions to other medications can cause runny poop in newborns. For example, medications such as anti-seizure drugs, acetaminophen, and NSAIDs like ibuprofen have been known to cause stomach-related symptoms like nausea, vomiting, and diarrhea in children.

Antibiotics

Antibiotic-associated diarrhea typically begins between the second and eighth day of taking an antibiotic, but it can also start on the first day and last for a few weeks after finishing the course. It is more common in children under two years old and can occur with any type of antibiotic. One in five children who take antibiotics will experience this side effect.

If your newborn is experiencing diarrhea due to antibiotics, here are some things you can do to help:

• Continue giving the antibiotic as prescribed, unless otherwise advised by your doctor.
• Ensure your newborn stays hydrated by offering them water frequently. Avoid fruit juice or soft drinks, as they can worsen diarrhea.
• If a rash develops around the anus or diaper area, gently wash the area with water and apply a layer of petroleum jelly, zinc-based cream, or diaper rash cream.
• Probiotics may be recommended by your doctor to help restore the balance of "good" bacteria in the intestines. However, do not give your newborn any probiotics or medicines without consulting your healthcare provider first.
• If your newborn experiences severe diarrhea, blood in the stool, or other concerning symptoms, contact your healthcare provider right away.

It is important to note that antibiotic-associated diarrhea can increase the risk of dehydration, especially in babies less than 12 months old. Signs of dehydration include decreased urine output, crankiness, fatigue, and a dry mouth. If you suspect your newborn is dehydrated, seek medical attention promptly.

Changes in mother's diet (if breastfeeding)

Changes in a mother's diet can cause runny poop in newborns if they are breastfeeding. This is because the food consumed by the mother can be passed to the baby through breast milk. For example, coffee, cola, or herbal teas may cause a breastfed baby to have more frequent or looser bowel movements.

It is important to monitor a baby's poop to determine whether they are healthy. In the early weeks of life, the baby is still establishing their eating and pooping habits. Monitoring their poop during this time can help parents and caregivers decide whether a baby is healthy and getting enough food. Every baby is different, so it is important to pay close attention to their usual pattern. A change in this pattern might signal a problem or could just be a sign of a change in the baby's diet or the diet of the person breastfeeding.

Breastfed baby poop is usually soft and runny, and this is completely normal. However, very watery poop might be a sign of diarrhea. Diarrhea can be caused by a viral, bacterial, or parasitic infection, a food allergy, or even drinking too much juice. It is important to track the colour, frequency, and consistency of a baby's poop, as one of the consequences of diarrhea is dehydration. Infants are more susceptible to dehydration, so be on the lookout for symptoms such as little to no tears when crying, fewer wet diapers than normal, lethargy, and a sunken soft spot on the top of the baby's head.

If you suspect that something in your diet is causing your breastfed baby to have runny poop, try removing that food or drink from your diet and see if the baby's poop returns to normal.

Changes in baby's diet

Introducing solids to your baby's diet can cause runny poop. This is because their digestive system is still adjusting to the new foods. You may notice a broader variation in the colour of their poop, which may even take on the colour of the food they ate.

Breastfed Babies

Breastfed babies tend to have runnier stools than formula-fed babies. Their poop is usually soft, runny, and yellow in colour—like English mustard. It may also be bright green and frothy if they are nursing for short periods on each breast and getting more foremilk than hindmilk.

Formula-Fed Babies

Formula-fed babies' poop tends to be firmer and pale brown or yellow-green in colour. Their poop typically has a consistency similar to toothpaste, which is thicker than that of breastfed babies.

Combination-Fed Babies

For babies who are fed a combination of breast milk and formula, their poop could vary and be seen as anything between the two types described above.

After Starting Solids

Once your baby starts eating solid food, you will notice a significant change in stool texture. Their stools will get firmer and the texture will be similar to a cooked sweet potato.

The frequency of bowel movements will also decrease as solids bulk up the stool, and there is usually less fluid being consumed.

Solid food also produces a stronger odour.

What to Do if Your Baby Has Runny Poop

If your baby has runny poop, it is important to keep them hydrated. Ensure that they are drinking enough formula or breast milk. If they are older and eating solids, try to serve foods with a high water content, such as watermelon or cucumbers, and encourage them to drink water from an open cup with meals.

If your baby also has a fever, appears to be in pain, or is irritable, seek medical attention right away.

Frequently asked questions