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Bloody Baby Poop: Cause And How To Treat

Milk soy protein intolerance (MSPI) is a relatively common food intolerance seen in infants. It is caused by the inability to properly digest the proteins found in milk and soy. The proteins cause the lining of the GI tract to get inflamed and damaged. When this happens, the stool starts to get mucous and blood in it, and the infant gets really fussy (they cry all the time because their gut hurts). The diagnosis also goes by the name of food protein-induced colitis (which just means inflammation of the intestines).

MSPI should not be confused with lactose intolerance. Lactose intolerance is caused by a deficiency in the enzyme that breaks down the lactose (a milk sugar). It is very rare for lactose to cause a problem in infants.

There is no specific test to diagnose MSPI. It is diagnosed by history, physical exam, and response treatment. As for treatment, there is no specific medication. The treatment is an elimination diet. If the baby is breastfed, mom has to have a diet completely free of cow’s milk and soy. The diet is not for the faint of heart. Practically everything has milk, butter, or soy it in (not just cheese and yogurt, think breads, sauces, tofu, etc.). Frankly, my hat goes off to the moms who can do it (I don’t think I’m that disciplined). If the baby is formula fed, you have to change to hypoallergenic/hydrolyzed formulas (e.g., Alimentum and Nutramigen). On occasion, I’ll have a baby that is so bad that I have to move to an amino acid-based or elemental formula (Neocate or Puramino). Prep yourself, these are all really expensive and there isn’t a generic available. Also, FYI, the formulas generally don’t taste as good and can cause stinky poop (I mean, more than usual).

Time is a trick with MSPI. It can take a while to show up (because the gut isn’t born inflamed and damaged, it takes time for it to happen) and it takes a while to recover after the diet has been changed. So don’t expect overnight onset or improvement (generally two weeks minimum).

The good news in this miserable diagnosis is that it tends to be a problem of infants only. Most infants outgrow the intolerance by the time they are a year (some even younger).

Thanks to the parents who let me snap of a pic of the poop their baby had in clinic. It’s classic MSPI poop.

The Poop Rules

Thanks M.B.G. from Utah for your question about what is normal baby poop.

There isn’t a day that goes by that I don’t field a question about whether or not a baby’s poop is “normal.” The reality is that baby’s stool is changing constantly, so it’s hard to know what is normal and what to worry about.

The Normal Transition

When a baby is born, his/her gut isn’t colonized with bacteria. Bacteria are required to digest food. So, the first few stools are sticky, tar-like, and black. As an infant eats breast milk or formula, the gut will get colonized and the stool will “transition.” The stool will change from tar-like and black to greenish/brown and finally end at yellow and seedy. How quick this happens depends on each individual infant’s gut and the amount of food (breast milk or formula) the infant is eating. Most infants transition in 2-5 days.

The Poop Rules

After the initial transition, each baby’s poop will vary quite a bit. Over time I have developed what I call the “Poop Rules.” These are rules of my own creation which essentially help parents decide what is normal (no big deal, don’t worry) vs. something could be wrong (your baby needs to be seen).

  • Color. When your baby is first born, the stool will be black. After the stool has changed from black to another color, it should NEVER go back to black. The poop should also NEVER be red (like blood) or white (that means another medical problem altogether). Bottom line, as long as the poop isn’t black, red, or white, another color is acceptable. The most common colors are yellow, brown, orange, and green.
  • Consistency. Normal baby poop is anything from pretty watery with a few particles (like seeds) to thick mush or paste. You have a problem if your baby’s poop is straight liquid (like pee) or hard like a rabbit pellet/marble.
  • Frequency. Babies poop at all sorts of intervals. Some poop every time you feed them, while others go once every few days. The American Academy of Pediatrics says that it’s normal for a baby to go up to five days between stools. Personally, I think five days between pooping is a long time and tend to use the three- or four-day rule. Anecdotally, it seems that breastfed infants tend to go more frequently than formula fed infants (I think it has to do with the fact that breast milk is easier to digest than formula). So, as long as your infant’s stools fall into the “Poop Rules” norms, then you can breathe a sigh of relief and stop worrying. If, however, your baby’s poop doesn’t meet all three areas of normal, then you need to make an appointment to see your pediatrician.

Diet Changes

It is also worth noting that every time you make a change to your baby’s diet (e.g., go from breast milk to formula or start solids) that it is common for your baby’s stool to change. You can get temporary diarrhea or constipation. Generally, it is a good idea to allow your baby’s system to work it out. If however, you find that your baby starts to get outside of the “Poop Rules,” you may want to consult with your pediatrician about ways you can help your baby make the diet transition.