The nipple size for your baby’s bottles will depend on if they are formula-fed or breastfed, their age, and other readiness cues. Nipple size is essentially the flow rate – how fast your baby can get liquid will depend on the labeled nipple size.
However, age isn’t always the best determinant of nipple size, as all babies are different. There are other signs besides age to indicate when your baby is ready to move up a size, such as:
- Sucking hard.
- Flattening the nipple.
- Getting aggravated (squirming, kicking, pushing the bottle away, etc.).
- Smacking at the bottle.
- Taking a long time to feed (30 min. to 1 hour).
- Eating less at feedings, but getting hungry again soon after.
If your baby isn’t showing any signs of frustration or taking forever to eat, there is no need to move up a size. But if your baby is showing some of these signs, give the next size up a try and see how your baby does. It’s all about trial and error.
If you do move up a size and your baby is gagging, coughing, choking, or dribbling milk out of the corner of their mouth, then the nipple flow is too fast and you will need to go back down a size. You may also need to move back down a size if your baby is exceptionally uncomfortable shortly after feedings, as the fast flow may have been too much for their digestive tract.