The Average Weight of a Newborn

It's one of the most frequently asked questions following the birth of a newborn: "How much does he weigh?" Throughout a woman's pregnancy, many people like to speculate about the weight of her future baby, with little to go on other than the size of the bump. That can often be misleading, though; a large bump doesn't necessarily lead to a larger-than-average baby. A newborn's weight can be affected by several factors.

Average Newborn Weight Range

If your newborn weighs between 5.5 and 10 pounds at birth, she's within the average range of weight. According to Heidi Murkoff, author of the bestselling pregnancy book "What to Expect When You're Expecting," 95 percent of newborn babies fall into this range. The average baby weighs 7.5 pounds. If a baby is born who weighs less or more than the average weight range, she may receive a little extra attention from medical staff to make sure she has no health problems.

Newborn Weight Loss

Newborn Baby

The Size of a Newborn Baby

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A baby typically loses 5 to 10 percent of his birth weight after being discharged from the hospital, which is due to normal fluid loss. A formula-fed baby may lose 5 percent of his birth weight, while a 7 to 10 percent weight loss is normal for a breastfed baby, says the American Pregnancy Association. The lost weight (and possibly more) will reappear within 10 to 14 days. Your pediatrician will monitor your baby's weight throughout the first weeks and months of his life to ensure he is growing at a healthy rate.

Boys vs. Girls

Newborn baby boys tend to be heavier than their female counterparts. However, the differences are slight. On average, boys weigh less than a pound more than girls, according to the American Academy of Pediatrics. Boys also tend to be around 1/2 inch longer than girls.

Premature Babies

Newborn Baby

How Much Weight Do Newborns Gain?

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Babies who are born on their due date or later tend to be heavier than those who arrive earlier. A premature baby (born before 37 weeks gestation) is likely to be lighter than a full-term baby. Premature babies born between 34 and 37 weeks gestation aren't likely to be much lighter than full-term babies, but those born at 32 weeks gestation or earlier won't have had the chance to develop much body fat, so they appear fragile and may weigh as little as 1 pound.