A: It's natural to be concerned if you think your children are not growing at a healthy pace, but before you worry, there are several factors to consider. First, if your twins were premature, your doctor will be evaluating their growth based on when they were originally due, not by their actual birthday. That means if they were born two months early, they should be about the size of a 4-month-old baby. Doctors usually expect most preemie twins to catch up in the first few years. If they're achieving their developmental milestones on time and seem happy and healthy, then all is probably well.
To ease your fears, ask your pediatrician to explain your babies' growth charts. If your twins are making consistent progress along the normal curve of the growth chart (even if it isn't by leaps and bounds) then they're most likely fine. Doctors only start to worry when a child's weight gain slows to the point where they rank below the third percentile or if they are drifting off their previous growth curves. So don't become too obsessed with the numbers of pounds and ounces, but focus more on their progress, which can speed up or slow down and still be normal.
If at any point your doctor becomes concerned that your twins are not growing fast enough, she may decide to order thyroid tests, other blood tests, or stool and urine samples to make sure that your children are absorbing and processing calories properly. She may even ask to watch you nurse or bottle feed to be sure your babies are sucking and swallowing adequately or may request that you keep a log of what the babies eat each day. To help your twins start increasing their calories, your doctor may place them on a high-calorie formula as well as address any underlying issues that may have been interfering with their ability to thrive, such as chronic diarrhea, acid reflux, or a sucking or swallowing disorder.