Probably not. Though growth charts help in spotting such fluctuations, the reality is that a baby's growth is often marked by variation -- some will have a nice even curve, and some will have peaks and valleys. Because they grow in leaps, it's normal for babies to slide up and down the charts a bit as part of typical growth patterns. The key is how fast and drastic the transition is. If your baby has been at the 50th percentile and drops to the 5th, for instance, the doctor will want to explore why the growth pattern has been interrupted. Possible causes include illnesses such as diabetes or other endocrinologic problems. There are also conditions that could lead to a dramatic jump in growth. More often, though, the cause is a growth spurt or improved nutrition. --Cammie McGovern
Originally published in the June 2001 issue of Parents magazine. Updated 2009.