While full-term babies are evaluated based on their actual age, a premature baby is assessed based on her corrected age (also called adjusted age), or how old she'd be if she had been born on her due date. Take, for example, a baby born three months early: "When she's 6 months old, we don't expect her to do 6-month-old tasks. We expect her to do 3-month-old tasks," explains Dr. Barden. "If she's meeting the 3-month milestones, then she's developing appropriately for her corrected age." (Vaccines are the one exception to the corrected-age rule. "Immunizations should be given based on a child's chronological age," he notes.) By age 2, the range of normal development is so wide that there aren't distinctions, says Dr. Barden.
A preterm baby's physical growth is also assessed based on adjusted age. Your child's doctor will be looking at how quickly your son is growing and will want to see that he is growing parallel to the growth curve, even if his height or weight (or both) is below the average for his age group, says Dr. Barden. "Premature babies who were born extremely early, who were extremely small for their gestational age, or who have severe ongoing medical problems may be small compared to their peers for some years," he adds. "Many of them will continue to grow somewhat faster than their peers through the elementary school years, catching up to the average, year by year, for quite a while."
However you add it up, nothing could be sweeter than watching a baby who once battled to breathe develop into a happy, active kid. "Even though I already had two children, caring for Logan was like taking Parenting 101 all over again. Raising a full-term child doesn't prepare you for parenting a preemie," says Milder. "You start out as a spectator -- many of us can't hold or touch our children for weeks or months -- but slowly and surely, your job becomes hands-on. Day by day, you might not notice it, but month by month, you will see prematurity loosening its grip on your child."