It doesn't matter your baby's age, when their pediatrician tells you they're underweight it can send parents into a panic. Knowing how to help your baby gain weight in a healthy and safe way isn't one of those things that just comes naturally, especially since there are a lot of factors at play. With the right support, though, it is definitely possible to help your baby pack on some pounds.
First and foremost, never just assume your baby is underweight and start giving them extra calories without first talking to your pediatrician. "If your baby is not gaining weight appropriately, the most important thing to do is to work with their doctor to figure out what’s wrong," David L. Hill, M.D., FAAP, spokesperson for the American Academy of Pediatrics, tells Romper in an email. Working with the pediatrician is so important because if a baby is underweight and feeding isn't the issue, there could be an "underlying problem such as GERD (gastroesophageal reflux disease), prematurity, or something worse," Dr. Hill explains.
Helping Baby gain weight with extra breast milk and fortified formula
If your child's physician has instructed you to help your baby gain weight, pediatrician Sara DuMond, M.D., FAAP, medical advisor for Dr. Brown's, says there are some simple ways to do so. "If breastfeeding, you may want to pump and add an extra bottle of expressed breast milk into their feeding schedule," or you can also try "human milk fortifier which is a way to add calories to expressed breast milk." For full-term infants consuming standard formula, Dr. DuMond notes there are "special formulas that contain 22 or 24 calories per ounce" (a standard baby formula is 20 calories per ounce) that your pediatrician may advise you to switch to until your baby has gained some weight.
Adding calories if Baby is eating solid foods
For little ones who have added puree foods to their diet, Dr. Hill says, "Offering feeds after every nursing session can be helpful." Or, you can add the breastmilk or formula right into the puree so it's all in one feeding, suggests Dr. DuMond. Your doctor may also advise giving your baby an extra serving of iron-fortified baby cereal daily or mixing pureed foods into solid foods, she says. She also advises parents to monitor liquid intake before meals, because "solids will be packed with more calories than liquids [and] if baby’s belly is full on formula or breast milk, they may not have an appetite for solids."
Signs Baby needs to gain weight
Again, none of these measures should be taken without first discussing weight with your pediatrician, especially because your baby's general build may mislead you into thinking they're underweight. "The growth curves really tell us the whole story," Dr. Hill explains, "Babies who start skinny usually stay skinny, and babies who start chunky often stay that way. As long as your baby is staying on their own growth curve, you can breathe a sigh of relief." Some symptoms that should definitely signal a call to the pediatrician include "dark, concentrated urine and not soaking diapers overnight, inability to go longer than 2 or 3 hours at a time without expressing hunger cues, infrequent stools, or a sunken soft spot on baby's head," says Dr. DuMond.
Once you've been instructed to help your baby gain some weight, make sure you're staying in touch with their pediatrician throughout the journey. "Parents should never make determinations about babies being over or underweight, on their own, without the guidance of a pediatrician," says Dr. DuMond, so the process really needs to be a joint effort from start to finish. Hopefully, that process won't take long at all, though, and you'll be back to typical feedings in no time.
David L. Hill, M.D., FAAP, Spokesperson for the American Academy of Pediatrics & Author of Co-Parenting Through Separation and Divorce: Putting Your Children First
Sara DuMond, M.D., FAAP, Pediatrician and Dr. Brown's Medical Expert