Doctors often use weight as an indicator of how well newborns, who typically lose a percentage of their birth weight within their first few days of life, are breastfeeding. But now a study, published in the International Breastfeeding Journal, is showing that weight loss in newborns may actually be a result of the IV fluids given to women during labor and not poor breastfeeding.
Researchers from the University of Ottawa looked at the relationship between the maternal IV fluids given during labor (or before a cesarean section) and newborn weight loss, and according to a release:
They found that during the first 24 hours following birth there was a positive association both between the IV fluids given to mothers before birth and neonatal output, and between the neonatal output and newborn weight loss. 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.
"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," said principal investigator Prof Joy Noel-Weiss from the School of Nursing at the University of Ottawa's Faculty of Health Sciences. "It appears 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."
It's common for doctors to tell new moms to supplement or even replace breast milk with formula if there is a drop in a newborn’s weight, and Noel-Weiss hopes this study will help medical professionals make more informed decisions:
We should reconsider the practice of using birth weight as the baseline when calculating newborn weight loss in the first few days following birth. For mothers and their breastfed babies, accurate assessment of weight loss is important. Although more research is needed, based on our findings, we would recommend using weight measured at 24 hours post birth as a baseline.