Babies typically lose weight after birth, before they start to gain. For years, doctors have advised that a baby should lose no more than 7 percent of his birth weight during the first 5 days, be back to his birth weight by day 10, and after the first 5 days, gain about 4–8 ounces each week or 1/2–1 ounce each day for the next three months.
A recent study of weight change in nearly 150,000 healthy babies found that it is “not uncommon” for newborns to be below their birth weight 10 to 14 days after delivery. About half of newborns were at or above their birth weight at 9 days (vaginal delivery) or 10 days (cesarean section) of age, but about 14 percent of babies born vaginally and 24 percent of those born by cesarean had not regained their birth weight by day 14. For some babies, slower return to birth weight does not indicate a health problem.
Still, if your baby loses more than 7 percent of her birth weight or gains weight slowly in the early days and weeks following her birth, your baby’s health care provider may ask you to bring your baby in for weight checks. A review of your breastfeeding routine along with periodic weight checks will ensure that your baby is getting enough to eat and that there are no underlying health issues. (Watch our video “How Can I Tell My Baby Is Getting Enough To Eat?”)
Parents of very slow gaining babies are sometimes asked to weigh their baby on an infant scale before and after a feeding to determine the exact amount of breast milk taken at each feeding. Another option would be to count your baby’s wet and poopy diapers. Output is usually a good measure of intake. Look for three or more poopy diapers a day by day 3 and six or more wet diapers a day by day 5. Your baby’s urine should be clear or pale yellow in color indicating good hydration. As babies grow, their stool patterns change. After 4 weeks of age, some babies continue to poop after every feeding, while others poop only once every other day, or once every 3–5 days. (Click here for more scoop on poop.)
Ultimately, many babies will double their birth weight by 4 to 6 months of age and triple their birth weight by their first birthday, but this is not true of all babies. Babies who gain more slowly or more quickly may be perfectly healthy too. Your doctor will monitor your baby’s growth over time (her weight, length, and head circumference) to ensure that your baby is getting all of the calories and nutrients she needs.