Hi D.
My Daughter has had this problem since birth. I went to alot of different Dr.'s to see what options I had. Most of them said to change her formula to soy. But my Cousin said don't cause their poop smells really bad and it didn't help her. So I decided to try the poop drops and she had a belly ack most of the time and cried alot. One Dr. said to give her a spoon of Mineral Oil and another said Olive Oil. I tried both and the Olive Oil was the best one and it's natural so it's healthier. Make sure she drinks alot of water too and rubbing her tummy helped a lil. If she gets really constipated you can try pushing her legs back while they are trying to get it out. I know it doesn't sound fun but we didn't it. Once your child is older you can smash up in a food processor Broccoli and other stuff high in fiber. We only have this problem now when she stays at her Grandma's house cause her grandpa doesn't listen to me when I stress the important of staying away from junk food and eating stuff high in fiber! One Dr. said it could be stress from going to one house to another.
I hope this helps cause it took me forever to seek someone to help me after all I think we saw like 15 different Dr.'s since it was horrible to see our first child with this problem and the crying was a nightmare!
Merry Christmas to you and your Family,
M. B.