You could say that I’m the kind of pediatrician who believes that a bottle is a bottle. Technology may be changing that.
A study out of Boston Children’s Hospital published late last year in the journal Pediatric Research compared the way babies fed from hard-walled bottles (Avent) and with that of soft-walled bottles (Playtex DROP-INS system). Using sophisticated instruments the researchers were able to simultaneously measure breathing, sucking, swallowing and blood oxygen in babies when feeding from each type of bottle system. They were able to identify differences in the way babies feed and breath with each bottle system and compared that with breastfed babies.
Some of the findings were very interesting:
Breastfeeding. Breast fed babies are able to separate swallowing from breathing.
Soft-walled bottle. Babies fed with the soft-walled bottles, like breast fed babies, coordinate their swallowing and breathing. They swallow less frequently and are less likely to swallow while breathing.
Hard-walled bottle. Babies fed with hard-walled bottles swallowed randomly and tended to swallow more frequently. Levels of blood oxygen in these babies was lower when compared with those babies who were breast fed or fed with soft-walled systems.
So despite popular trends towards certain bottles, it would appear that the Playtex DROP-INS system does a better job of helping a baby coordinate their sucking and breathing. And as the authors describe, this coordination is likely to lead to less air swallowing. As I discuss at length in my book, Colic Solved, air swallowing is the root of all gas in babies and anything we can to minimize it’s access can only help a baby’s cause. 
As technology advances, our ability to identify subtle differences in the way babies feed with different bottles will change the way we look at feeding. Once a market driven process, our decisions regarding feeding systems will ultimately be defined by physiologically identifiable differences such as those seen in the Goldfield study.
As always, the breast is best. For those who can’t, the future looks bright.