Today Roscoe hit 4lbs and 10.4oz. As I mentioned about his digestion issues, the doctors put him on an all-formula diet so they can determine if he has an allergic reaction to milk (lactose intolerant). They also saw him gaining weight, but not at a rate that they would like him to gain. Basically, Roscoe was trending upwards in weight at the same rate as a normal baby. This meant that Roscoe would never catch up with where his weight would have been without the IUGR. The doctors want Roscoe to gain weight faster than a normal baby would gain weight.
As the new year has just rolled around, many of the people reading this blog may have started (and already given up on) a new years resolution to lose weight. The formula for losing weight is to burn more calories than you consume. Since Roscoe has been consuming and digesting more food lately (he is up to 42mL per feeding), the doctors concluded that it also means he's burning more energy as well. Since he's just a baby laying in a crib, they suspect he's burning an abnormal amount of energy trying to breathe. This would also explain why Roscoe has been stuck at 28-30% oxygen for around 2 weeks now.
To help Roscoe gain weight, they increased his breathing support to ease the strain on his lungs. Once he gains weight he'll hopefully have healthier lungs and be able to decrease his breathing support.