Is Your Newborn Losing Too Much Weight? Now There's a Tool to Help You Know

I've always envied how moms of bottle-fed babies know exactly how much milk their kiddo has ingested during a meal. As a breastfeeding mom, any guess I made was just that. And while this piece of information wasn't so crucial once I had been nursing for a while, it was everything to me in the first days of my baby's life. After all, a belly full of milk meant a certain number of dirty diapers and a steady, reassuring rise on the growth chart.

But as I found out the hard way, a breastfed newborn often loses weight in the beginning until milk production begins in earnest. Though some trimming down is to be expected, too much can lead to dehydration or hyperbilirubinemia, a type of jaundice. A normal range of how quickly and how long the weight loss lasts hasn't been fully known -- until now.

A team of researchers has developed the Newborn Weight Tool, or Newt, which compares a newborn's weight in the first few days of life against those of other babies. The free tool relies on hourly birth weights from more than 100,000 breastfed newborns delivered at Northern California Kaiser Permanente hospitals (between 2009 and 2013) to make the comparison. A handy graph shows moms and pediatricians where the baby's weight falls on the growth chart so they can figure out if it's time to supplement with formula or continue nursing exclusively.

"For parents who are concerned about their newborn's weight loss, they can be shown how their baby compares to the study sample, and whether they fall into a dangerous zone," says Valerie Flaherman, M.D., lead author of the study and a pediatrician at UCSF Benioff Children's Hospital San Francisco. "It also provides a tool for pediatricians to determine which babies are at high risk, addressing a major clinical gap because there are no current criteria for newborn weight loss."

Personally, I would have appreciated such a tool after my baby was born. I knew I wanted to breastfeed exclusively as long as I could, and I figured that when the time came, whatever colostrum I produced would be more than enough to sustain him until the milk came in. Yeah...not so much. When our kind pediatrician gently suggested after the first 24 hours of nursing that we supplement with a bottle -- just for now -- I felt like someone punched me in the gut. I don't know if it was the freewheeling hormones, but I took the unexpected news pretty hard. If I wasn't second-guessing the quality of my colostrum, then I was trying to shake the feeling that I was already a failure as a mom. It didn't help that my lactation consultant pooh-poohed the idea of supplementing and encouraged me to go rogue and refuse the formula. I ended up siding with my doctor, but I wish I had a graph or point of comparison to help me make a more informed decision.