The Newborn Weight Tool (Newt)

An article published in the online ScienceDaily magazine, based on information from Penn State Milton S. Hershey Medical Center, reports on a study detailing the weight loss patterns of exclusively breastfed newborns using weights obtained from a sample of over 100,000 Northern California babies. The article states, “Women do not immediately produce high volumes of breast milk in the first days after childbirth. Instead, mothers at first secrete small amounts of colostrum, which contains high concentrations of nutrients and antibodies for the baby. During this period, almost all babies experience some initial weight loss, which can cause concern from new parents” over potential risk for dehydration or jaundice. “Mothers sometimes believe this weight loss means their baby is not getting enough breast milk, leading them to supplement their baby with infant formula, a practice pediatricians hope to avoid when possible.”

The Newborn Weight Tool (Newt) has been developed based on the large-scale sample of early birth weights of breastfed newborns at Northern California Kaiser Permanente hospitals between 2009 and 2013. “The tool plots a baby’s weight percentile at any given time in the first few days following birth and compares it with the large sample of newborns, to allow an individual mother to see how her newborn compares with these normal patterns, which in most cases will be reassuring.” The tool will also assist pediatricians in their determination of which babies are at high risk, addressing a previous clinical gap. The tool was developed by the study’s senior author, Ian Paul, MD, professor of pediatrics and public health sciences at Penn State College of Medicine and pediatrician at Penn State Hershey Children’s Hospital, and Eric Schaefer, MS, a statistician at Penn State College of Medicine, along with researchers at UCSF and Kaiser Permanente hospitals. The tool is available at

The findings of an earlier (2011) study by a Canadian group of researchers, led by Professor Joy Noel-Weiss of the School of Nursing at University of Ottawa’s Faculty of Health Sciences, and reported earlier in ScienceDaily, also has relevance in this area. “Nurses, midwives, lactation consultants, and doctors have long wondered why some babies lose substantially more weight than others even though all babies get small amounts to eat in the beginning.” The findings of the study by Dr. Noel-Weiss and her research team found that, for women who receive IV fluids during labour, “it appears that neonates exposed to increased fluids before birth might be born overhydrated, requiring the baby to regulate his or her fluid levels during the first 24 hours after birth.” They found that at 60 hours post birth, the time of the average lowest weight, there was a positive relationship between maternal IV fluids and newborn weight loss, leading them to recommend 24 hours post birth as a more appropriate baseline, compared to used birth weight as a starting point for measurement of postnatal weight loss. The research team created a protocol for clinicians to collect and analyze ongoing data in their own maternity site to help them make informed decisions when assessing newborn weight changes.

Dr. Noel-Weiss RN IBCLC chairs the International Lactation Consultants Association’s Ethic and International Code Committee and is working as the principal investigator on a research study on Transmasculine Individuals’ Experiences with Pregnancy, Birthing and Feeding Their Newborns, funded through an operating grant from the Canadian Institutes of Health Research—Institute of Gender and Health.