M.S.
Arching is a classic sign of stomach/acid distress. You may also want to add some "baby gas medicine" - simethicone drops to her bottles or to give after nursing or even in the middle. Experiment to see if the timing helps it work better. Less gas = less pressure on that little belly. The name brand is mylanta, but the store brands are the same stuff for much less $. It's a staple at my house. My pediatrician says that all babies will reflux to some degree because the muscle control just isn't there to hold back the contents of a full tummy. Out of 4 babies, one was the worst reflux / throwup / spit up of them all. He took two medicines, one for acid and one for nausea. But honestly, he was just a little pig and never knew when to stop nursing. He was almost 18 months before he ever got the message patterns from his stomach to his brain to register that he was full! In hindsight, he probably didn't even need all the medicine that I forced down him. If you're bottle feeding, you may want to try some other types of bottles/nipples that may produce less gas. I also got a good home remedy tip that I used for my fussy little girl who had a nightly crying ritual that seemed a mix of colic and gas pain. I made a tea by boiling fennel seed. I added enough sugar to make it mildly sweet and gave it to her (warmed in a bottle) after her last feeding of the evening. 2 to 4 ounces just before bed each night worked wonders. I'd make about a quart of tea with two heaping tablespoons of the fennel seed. I'd let it lightly boil until the color was a rich yellowy brown. It kept well in the fridge in a tightly sealed glass container. Hope this helps!