Baby Care: Differences in Stool Between Formula-fed Babies and Breastfed Babies - Sunday Hug

Baby Care: Differences in Stool Between Formula-fed Babies and Breastfed Babies

Question of the Day

I am breastfeeding and my baby's stool seems to be too watery. They have frequent bowel movements several times a day. Could it be diarrhoea? I'm worried.

Did you know that the number of stools and their viscosity change depending on the method of breastfeeding?

Breastfed Baby’s Stool

Breastfed babies have much softer stools than formula-fed babies. The stool is watery enough that you might worry that it could be diarrhoea. The colour should be close to yellow, but there are many other colours. Newborns who are 1 to 2 weeks old and are breastfed have a bowel movement about 8 to 10 times a day, almost every time they feed.

mother with her children

This is because some of the components of colostrum have a laxative effect, which expels faeces quickly and promotes bowel movement as lactic acid bacteria proliferate in the child’s intestine.

As the stool stays in the large intestine for a shorter time, the stool becomes thinner and the frequency of bowel movement increases. After 3 to 6 weeks of age, the colostrum component disappears, and the number of stools gradually decreases. The average number of stools is about 4 times a day around 4 weeks of age and once a day after 2 months of age.

However, the frequency of bowel movements in breastfed babies at this time varies widely. Some babies have a bowel movement once or twice a week, and some babies have more than 10 bowel movements a day. As long as your baby is gaining weight properly, you can consider everything being within the normal healthy range. Babies who are exclusively breastfed rarely develop constipation. When weaning begins, the bowel movement pattern of breastfed infants gradually becomes similar to that of a formula-fed infant.

baby lying down

Formula-fed Baby's Stool

Formula-fed babies have stools that are much muddier in colour than breastfed babies.
Formulated milk stays in the intestine longer than breast milk. The longer it stays in the intestine, the more water is absorbed. Therefore, they defecate less frequently than breastfed babies.

Formula-fed babies usually pass stool once a day. It is normal for your formula-fed baby to have a bowel movement at least once every 2-3 days. If your formula-fed baby hasn't had a bowel movement for more than 4 days, they may be constipated.

Tip: If you think the number of stools your baby is passing is too much or too little, check to see if your baby's weight gain is normal. Babies under 6 months should gain 20-30 g per day, and from the ages of 6 months to 1 year old, they should gain 10-20 g per day. If their weight gain is normal, you shouldn't worry too much about the number of stools. Also, look at the number of urine diapers. They should produce 5-6 urine diapers per day.

#Advice from Jeongho Seo, a Paediatrician

My child has green stools, is that okay? 

What component affects stool colour the most? It’s bile! Bile produced by the liver meets food in the duodenum. The food digested by bile passes through the small intestine and large intestine. At this time, due to bacterial activity in the large intestine, the green bile changes to yellow and then to brown.

However, if the stool passes through the large intestine faster than normal, the bile does not turn brown and remains green. In other words, seeing green stool can be interpreted as the bowel movement being faster than normal. If the bowel movement is a little faster, it is not a problem, as long as the child is growing and healthy.

four babies in swaddles lying down side by side

However, if your child shows pain along with green stool, or if there is a situation in which the child is stressed, there might be an issue. In breastfeeding infants, an imbalance of milk from breastfeeding can also be the cause of green stool.

If a breastfed infant has green stools and gas, loose stools, their stools have a sour smell, or they do not gain weight well, it might be because of consuming imbalanced milk during breastfeeding. If you are only breastfeeding your baby for a short time, your child will only eat whole milk, which is high in carbohydrates (lactose). This speeds up bowel movements. If a similar situation is suspected, breastfeed for a longer period of time and sufficiently so that your baby receives the range of nutrients produced in breast milk.

If your formula-fed infant has green stools, gas in the baby's tummy, loose stools, or no weight gain, you might want to consider that they have lactose intolerance or milk allergy symptoms. In this case, after consulting with a specialist, you can choose a soy milk or milk allergy-friendly formula (hydrolyzed protein powder).

Does your child also have bloody stools? If diarrhoea symptoms are also present, enteritis may be suspected. One of the simplest causes of your child having green stools might be because they’ve eaten green food! Green stools may appear when your child eats leafy vegetables or takes iron pills. If this is the case, don't worry. They don't have to stop taking their medicine or eating vegetables.

Author: Doctor Seo Jeong-ho
- Representative Director of 'Yonsei Hangyeol Pediatrics', Gangseo-gu, Seoul
- Pediatrics Specialist