As a pediatric surgeon with a special interest in intestinal issues, I am often contacted by worried parents regarding their baby's infrequent bowel movements. This can be caused by a variety of
problems such as blockages of the intestines or abnormal intestinal function (including a condition called Hirschsprung's disease); but most frequently babies are just efficiently absorbing and thus not needing to poop very often. This is especially true for breastfed babies. So, how can a parent tell the difference?
I would offer the following "red flags" as issues that may indicate a problem needing further medical evaluation:
A baby's first stool should be within the first day of life and certainly within the first 48 hours. In fact, over 95% of normal babies will poop in the first day of life. While the fog of the initial days of new parenthood may make the time of your child's first poop hard to remember, the second warning sign is a baby repeatedly needing help to have a bowel movement.
If parents find themselves having to regularly help with suppositories and/or rectal stimulation (for example using a rectal thermometer), then I would recommend contacting your child's doctor. A baby's belly can certainly look rounded after feeds, but a consistently firm and distended abdomen is concerning. A baby's main job is to feed and grow, so if they lose interest in feeding, that is another sign of a possible intestinal issue. Vomiting especially when dark yellow or green is never normal in a baby and should result in immediate medical evaluation.
On the reassuring side, if a baby is happily feeding, not vomiting, and has a soft abdomen then he/she is most likely fine. This includes some breastfed children going well over a week between stools.
In summary, look for “red flags” to signal a possible blockage of the intestines, and if these are present then it is best to seek medical attention.