Babies don't all come from the same mold. Yours may be much bigger or smaller than her peers, but that doesn't necessarily make her any less healthy. One thing babies all have in common, however, is that they grow at a tremendous rate and that they can be expected to hit growth milestones at similar times.
Weight at Birth
Babies enter the world at various healthy sizes. However, the majority of full-term babies weigh between 6 lbs. 2 oz. and 9 lbs. 2 oz., according to KidsHealth.org, a part of the Nemours Foundation. Your newborn may weigh more or less than the average, but that doesn't necessarily indicate a health problem. Just in case, though, medical staff may pay extra attention to him to ensure that he is healthy.
Size Factors
A newborn baby's weight will likely be under the average if the baby is born before her due date, states KidsHealth.org. Other factors that might influence a newborn's weight include the sizes of the parents, whether the baby is part of a multiple birth, gender, whether the baby is a first or subsequent baby, the mother's health and nutrition during pregnancy, and the baby's own health, according to KidsHealth.org.
Typical Weight Gain
Your baby is likely to lose between 7 and 10 percent of his birth weight within his first days of life, but he is likely to be at his original weight by his second week of life, notes KidsHealth.org. At that point, he should begin gaining weight at a rapid pace of 5 to 7 oz. every week, and he should about double his birth weight by the time he is 6 months old, according to MayoClinic.com. His weight gain should slow down to about 3 to 5 oz. a week at that point, leading him to be at about triple his birth weight by the time he has his 1st birthday, explains MayoClinic.com.
Calculating Weight Percentiles
Your pediatrician will use growth charts to monitor your baby's growth over time. He will measure and enter her weight on a chart for all babies of the same age and gender, according to BabyCenter.com. If your baby is told that she is in the 25th percentile for weight, for example, she weighs the same as, or more than, 25 percent of babies her age and gender, but less than 75 percent of babies her age and gender. However, BabyCenter.com mentions that if your baby was born a few weeks early, the doctor may enter her weight on a chart for premature babies, or he might compare her with babies who are a few weeks younger.
Causes for Concern
Talk to your pediatrician if you're concerned that your baby isn't gaining weight as he should, or if you believe that your baby is losing weight. However, MayoClinic.com mentions that many babies go through brief times of halted weight gain or slight weight loss. On the other hand, your pediatrician may express concern if your baby's weight percentile is much higher or lower than his height percentile, or if your baby's weight percentile dipped dramatically from one appointment to the next, notes KidsHealth.org.
