Re: 4 month old suddenly straining to poop, but not constipa
I wouldn't worry about it. My baby often strained while pooping until he could stand and squat. Our pediatrician assured me that it is normal. The only other recommendation I can give is when he is straining either hold him upright with his feet supported by your hand or arm so that he is in a squat, or lie him on his back and push his legs up into a squatting position. Babies tense lots of muscles as they learn how to poop, and squatting forces certain muscles to relax making it easier to pass the poop.
K. Sophia - Mama to my little lactivore, the amazing Mr. X (11/10).