Re: Stomach Infections in Breastfed Babies?
The midwife and the pediatrician gave you basically good advice. Green poop in an otherwise happy, healthy, growing baby is not a big health problem. It's a "keep an eye on it" problem.
I am not sure I'd go with "stomach infection" as an explanation for the green poop. A more general term like " gastrointestinal illness" probably fits better. Gastro bugs are often viruses, caused by a rotaviruses, noroviruses, adenoviruses, etc. Bacterial infections are also possible culprits, but I think they're generally more severe than viral illnesses in this instance, because you're talking about infectious agents like cholera, salmonella, campylobacter, E. coli, leptospirosis... Generally those are much tougher infections and they cause a person to be a lot sicker than the viral infections.
Allergic reaction to something in your diet is possible, but it's unlikely that an allergy would wait until 4 months to manifest itself. In addition, babies with allergies tend to have poops which are not only green but also mucousy, and which may be specked or streaked with blood. You are also likely to see other allergy symptoms like excema, a red ring-like rash around the baby's anus, hives, maybe asthma, maybe poor weight gain. So, if the ony symptom you're seeing is green, slimy, stinky poop, think illness first, allergy only if the baby continues to have symptoms for a long time, and those symptoms worsen when you eat suspect foods (especially cow's milk, eggs, wheat, and soy, which are common allergens).
The final possible explanation for green poops is oversupply. Babies whose moms have an overabundance of milk will often experience something called lactose overload. This is not lactose intolerance, which is something that only develops in older children and adults who have lost the ability to produce sufficient lactase (the enzyme that breaks down lactose). A baby who experiences lactose overload produces a normal amount of lactase, but mom's milk is so rich in lactose that it overwhelms the normal lactase levels, producing green, stinky poops which can sometimes have flecks or streaks of blood. I don't think lactose overload is likely in your baby's case because it generally shows up earlier than 4 months, but if you happen to have a really large milk supply, it could be the cause. If lactose overload is the problem, then it's generally fixable, but it's also not a health problem.
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