I must have a bottle and nipple for every occasion. The best answer is: it's whatever your child will take.
I have 2 Dr. Brown's with 2 different nipples and a ton of different Avent bottles with no. 1 and 2 Natural and Classic nipples.
The most success I've had was with an Avent with a Classic no. 1 to reduce gas build up. However, I think the formula and how you prep before and after feeding addresses about 98% of the issues you'll have with feeding.
My son started on breast milk and some Standard 1 formula for the first 3-4 weeks, then a cramping sensitive formula for 6 weeks, but then he started screaming a lot during feedings. Now he's been on a hypoallegenic forumula for the past 2 weeks, and he's so calm during and after feedings, it's scary. He may have developed sensitivity to the previous formulas.
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