Why Newborns Lose Weight

Newborn babies are tiny enough, so when parents hear that their little one has lost weight after his first 24 hours, they can become concerned. But it's totally normal for newborns to lose weight in their first week, and most babies gain this weight back by their two-week checkup.

Cause of Weight Loss

According to Dr. Mark Widome, medical contributor to the Today Show, babies are born with extra fluid in their bodies, which prevents them from becoming dehydrated until mom's milk supply comes in. After birth, they lose this fluid, which results in weight loss.

Feeding Choices

According to Science Daily, formula-fed newborns usually lose less weight than breastfed babies while they are still in the hospital. This is probably because most mothers' breast milk doesn't come in for two to five days after delivery. Until milk arrives, nursing babies receive colostrum, which is thicker but less abundant than breast milk. For this reason, many nurses and parents decide to supplement breastfed newborns with formula. Supplemented babies usually have weight-loss patterns similar to exclusively breastfed babies. According to Tracy Hogg, author of "Secrets of the Baby Whisperer," infants who weighed less than 6 pounds at birth can't afford to lose 10 percent of their body weight, so it's best to supplement with formula until breast milk comes in.

Average Weight Loss

Widome writes that most newborns lose 5 percent to 10 percent of their body weight before they start to gain weight, which is usually at around 7 to 10 days old for a breastfed baby. Formula-fed infants often regain their birth weight in just a few days. Premature babies can take longer.

Effects of Weight Loss

There are no long-term effects of early weight loss, but if your baby doesn't begin to gain weight after the first week at home, contact your pediatrician. It might be hard to tell if she is getting enough to eat, especially if you are breastfeeding, but if she seems calm and satisfied after a feeding, then she's probably getting plenty. If she has four to five bowel movements a day, milk is moving properly through the digestive tract. After the first week, the normal range of weight gain is between 4 and 7 oz. a week, according to Hogg.

Helping Your Newborn Gain Weight

For formula-fed babies, weight gain usually isn't a problem, but breastfed babies can gain weight faster if mom's milk supply comes in quickly and she follows a frequent feeding schedule. According to Dr. Gwen Dewar from parentingscience.com, new moms who breastfeed every two hours usually begin lactating 24 hours earlier than moms who breastfeed every four hours. More-frequent breastfeedings increase a mother's prolactin levels, which signal her body to produce milk. Since colostrum is produced in small amounts, a higher-frequency feeding schedule helps babies compensate for the lower caloric intake with each feeding.