As parents, we watch our babies grow with awe. Yet few of us can resist comparing our child with others his age. We wonder: Is my chubby son destined to be fat? Is that taller, heavier baby healthier than my smaller, lighter child? Is the fact that my daughter isn't crawling a sign that she's developmentally behind?
The answers are no, no, and no. Furthermore, all of those comparisons won't tell you much about your own baby's progress, says Ben Danielson, M.D., medical director of Odessa Brown Children's Clinic, in Seattle. Like grown-ups, babies come in a multitude of "normal" shapes and sizes. And they hit developmental milestones according to their own inner timetables. Here, pediatricians share the nitty-gritty on growth -- and put your worries to rest.
At each checkup, your baby's weight, length, and head circumference are plotted on a growth chart compiled by the National Center for Health Statistics, a federal agency in Hyattsville, Maryland. Any number between the fifth percentile and the 95th is considered normal. Whether the measurements are high or low, they should follow a consistent curve over the first year. "Your baby's position on the chart means very little to us," says Robert Eden, M.D., a clinical assistant professor of pediatrics at Brown University Medical School, in Providence. "What matters is whether she's growing in a predictable trend." There are bound to be variations from checkup to checkup, but any dramatic change (a drop from the 50th percentile to the fifth, for instance) is a red flag, and your doctor will want to keep closer tabs on your child.
If your baby is below the 50th percentile in weight, you may be tempted to try to feed her more. Don't, advises Dr. Eden. Even babies below the "normal" range will be fine as long as their growth remains steady. "My 10-month-old's measurements have been in the third or fourth percentile since her birth," says Chris Anne Wheeler, a mother of two from Hopkinton, New Hampshire. "She has her own growth curve that parallels the usual curve." In addition, babies of Asian, Hispanic, and Pacific Islander backgrounds tend to be smaller, on average, than babies of other ethnicities. While the newest growth charts incorporate data from diverse racial and ethnic groups, you should still take your child's background into account.
We've all read the statistics about the boom in childhood obesity. But don't panic about your 6-month-old's chubby thighs. Your baby's weight does not predict future obesity unless it is radically out of proportion to his height. And no matter what your baby weighs, never restrict his food intake; he needs calories and fat so his body and brain can grow.
Conventional wisdom holds that a baby's height, weight, and head circumference should be in the same percentile. While that's often the case, don't fret if your baby's percentiles seem out of whack. "Both scenarios are common," says Cynthia Ferrell, M.D., an assistant professor of pediatrics at Oregon Health & Science University, in Portland. During a growth spurt, a baby's length may shoot up, or he may gain weight quickly, causing his growth-chart percentiles to diverge.
Of all your child's organs, her brain grows most rapidly, with the head expanding right along with it. That's why your pediatrician so conscientiously measures head circumference -- to ensure that the brain is developing properly. One way to tell that a baby is significantly undernourished is that she stops gaining height and weight, while her head continues to grow at a normal rate (the body automatically reserves calories for all-important brain growth). If a baby's head seems particularly large in relation to her height and weight, the doctor may measure the parents' heads, since this characteristic runs in families.
Although babies born preterm (before the 37th week of pregnancy) are small at birth, they grow faster than full-term newborns -- most likely because they're completing what would have been their in-utero growth. By 2, most premature babies have caught up with their full-term counterparts. But there are exceptions. Being a multiple or being extremely premature, for example, can affect a baby's future size, says John Walburn, M.D., a professor of pediatrics at the University of Nebraska Medical Center, in Omaha. "Some of the smallest preemies never quite catch up, no matter how well nourished they are."
Is your nine-pound newborn destined to be a linebacker? Birth size can predict adult size, but only when it reflects hereditary factors. "Many large babies drop to lower percentiles after six months of age. We say they're 'finding' their genetic potential," says Dr. Walburn. In other words, if you and your spouse are short and slight, your child is likely to be too.