My son was born prematurely. He was combo fed from the start. However, the formula he started out with constipated him really bad. He went days without having a bowel movement. My son would grunt as if trying to push and squirm all day long. This was concerning. So my husband and I started to research and found out that most baby formulas caused constipation due to certain oils used in the ingredients. The formula he was on at the time contained palm oil. We came across Byheart and loved that it had great reviews and testimonials. And best of all, no palm oil. We gave it a shot and we love it! My son loves it! He hasn’t had any tummy issues since we made the switch. For personal reasons, he is no longer combo fed and is solely on Byheart. It gives us, as parents, piece of mind knowing we picked a formula with choice ingredients that has helped our son.