When families are choosing a baby carrier, safety is often the primary concern. But some types of carriers may be affecting children in unexpected ways, according to a new study written by Boise State University researchers.
Baby carrier products feature a broad range of designs, with one of the most distinctive features being the width of the base of support between the infant’s legs. Using ultrasound imaging to explore how two designs of body-worn baby carriers (wide-base and narrow-base) may influence hip position, researchers found that wide-base baby carriers may have positive implications for hip development, while narrow-base baby carriers have concerning results.
“Understanding how infant musculoskeletal health may be impacted by commercial infant gear is important to ensure long-term hip health for babies,” said Erin Mannen, assistant professor of mechanical and biomedical engineering and director of the Boise Applied Biomechanics of Infants (BABI) Lab.
Researchers obtained coronal hip ultrasound images of 10 healthy babies and three babies with mild developmental dysplasia of the hip as part of the study. They evaluated important hip health parameters of healthy infants using inward-facing soft-structured baby carriers with a wide base and a narrow base. They then compared those findings to the parameters of those using a Pavlik harness, an orthopedic device used to treat hip dysplasia. Wide-base baby carriers hold infant hips in a position not significantly different than the Pavlik harness, meaning that babywearing in a wide-base carrier likely promotes healthy hip development
“This study adds more evidence that healthy hip position should be maintained when infants are carried; especially the 10 percent of infants that may have hip instability following birth,” said Dr. Charles T. “Chad” Price, medical director for the International Hip Dysplasia Institute.
“Parents want the best for their babies; they want them to grow up strong and healthy. That includes their long-term health. This research helps families understand hip-healthy baby carrying positions, the baby carrier options to look for, and can provide peace of mind that they’re following the most recent and up-to-date research.” said Joanna McNeilly, the founder and executive director of the Center for Babywearing Studies. The researchers note that babywearing provides many social and psychological benefits to caregivers and babies, and although the results of the study highlight concerns with use of narrow-base carriers, that long-term hip health is likely not impacted by short-term use of carriers.
Boise State’s BABI Lab is nationally and internationally known by the infant product industry for its work with the U.S. Consumer Product Safety Commission on inclined sleep products (now banned), crib bumpers (now banned) and infant pillows. The BABI Lab is one of the only labs in the world that uses traditional biomechanical experimental techniques to study infant interactions with commercial products.