Baby milk bottle teat.

Monitor for any change in feeding pattern or fussiness. Especially if u're still breastfeeding, some babies don't even need to change the teat level for a long time as the milk flow shld mimic tt of mom's. I only upgraded to the next level at 4+ month when my boy started to get fussy. He wld always finish his milk but there was a time he only took in about 60ml when his usual was 160-180ml at tt time. And it took him very long to drink too. Fussiness stopped once I changed the teat.