Has anyone mentioned a higher calorie formula for her? My son was born 5 weeks early, had an immature suck, and has sever reflux. Most formula's are 18-20 calories when mixed like the directions say. What we were told to do is make the formula 28 calories a serving. This meant mixing more powder for the same amount of water. This made the formula thicker to help with the sucking and choking issues but it also gave him the extra calories to help him gain weight. It is an actual equation on how you mix the formula so I would only do this under a Dr's advice.
If she has reflux, chances are the congestion might be slight aspiration. You can aspirate and not get deathly sick when the aspiration is only small amounts. For this reason, you think it's only congestion. If the problem continues, I would push for a swallow study to see if everything is working properly. My son has had 2 and they aren't as traumatic as they sound.
You want a bottle with a slow flow to stimulate the muscles she uses to suck. It is only through working those muscles that they get stronger. The higher calorie formula can come in handy there also as she won't eat as often but the meals will be more nutritious. Good luck
Mindy (Type 1 Dx'd 11/94..Insulin Pump)