Bowel movements can differ greatly among babies and change as they grow.
My fully-breastfed boy poo-ed up to 11 times a day in the early months, then once in up to 10 days at 5 months old.
He's now on solid + breastmilk, poos in alternate days.
As long as the poo is soft (fully breastfed babies have explosive poo), should be fine. Not necessary to poo after every feed since baby is on formula milk as well.
Regurgitating some milk after feed is common, as babies tend to take in some air when drinking. This can be for both formula and breastfed babies.
Burp baby well after feed by keeping his body upright and rubbing back + pressing tummy a little.
If baby throws up almost the entire feed a few times, then consult your pediatrician.
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