E.N.
Both of my babies were formula fed and we had the same problem. We started adding an extra ounce of water to each bottle and that solved the problem. I can't remember if my second baby was ever actually constipated, we may have just added the extra ounce of water to avoid the problem. As long as they were getting that extra ounce of water with each bottle, they didn't have any constipation. Hope this helps!