Baby-Carrying Method Impacts Caregiver Postural Sway and Pain During Prolonged Standing

Abstract

Background: Infant carrying is necessary for caregivers of babies. While in-arms carrying of infants is common, babywearing offers hands-free infant transport. Postural impacts of carrying methods are unknown. Objectives: Goals of this biomechanics study were to quantify differences in women holding infants in arms and in baby carriers compared with unloaded conditions during prolonged standing, and subgroup women into those who develop pain during standing (PDs) and those who do not (NPDs) to investigate differences in responses to baby-carrying conditions. Study Design: Single-subject design. Methods: Ten healthy nulliparous females (aged 27.4 ± 4.1 years) performed 15-minute quiet standing trials with each foot on a force plate in 3 conditions: holding nothing (unloaded), holding an infant mannequin in arms (arms), and holding an infant mannequin in a baby carrier (carrier). Participants completed a 10-cm Visual Analog Scale for pain before and after each trial. Results: Thirty percent of participants reported pain in the unloaded and carrier conditions compared with 50% in the arms conditions. Participants shifted their weight more frequently, spent more time in asymmetrical stance, and had INTRODUCTION Babywearing, the practice of transporting an infant or child in a carrier on the body, provides physical closeness of an infant to the mother or caregiver. The infant-mother proximity has been shown to have emotional, physical, and physiological benefits for the baby in both animal and human species. Stemming from survival instincts, separation from the mother is viewed as a life-threatening situation for offspring, causing them significant distress.1 Maternal carrying of the offspring has been shown to trigger a calming response demonstrated by central, motor, and cardiac signals in distressed infants.2,3 In addition, skin-toskin contact of premature human babies with their mothers or other caregivers, called kangaroo care, has been shown to decrease infant mortality rates, increase breastfeeding success, reduce agitation and sleep apnea, and improve infant respiratory and temperature regulation.4–8 Furthermore, a separate study has linked babywearing to a decreased likelihood of hip dysplasia in infants and young children.9 Babywearing allows the caregiver to be physically close to the baby while remaining hands-free. Physical closeness benefits the mother as well as the baby. Mothers across species show increased 1Department of Orthopaedic Surgery, College of Medicine, University of Arkansas for Medical Sciences, Little Rock. 2University of Denver, Denver, Colorado. 3Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles. 4College of Physical Therapy, Regis University, Denver, Colorado. Conflicts of Interest and Source of Funding: This study was funded by Ergobaby, Inc., and National Institute of General Medical Sciences of the National Institutes of Health under Award Number P20GM125503. The funding sources had no influence in study design, experimentation, analysis, or manuscript preparation. Corresponding Author: Erin M. Mannen, PhD, University of Arkansas for Medical Sciences, 4301 West Markham St, Slot 531, Little Rock, AR 72205 (emannen@uams.edu). DOI: 10.1097/JWH.0000000000000163 Research Report Baby-Carrying Method Impacts Caregiver Postural Sway and Pain During Prolonged Standing Erin M. Mannen, PhD1,2 Kathryn L. Havens, PhD3 Alexandra Kahney, SPT2,4 Erika Nelson-Wong, PT, PhD4 Volume 44 • Number 2 • April/June 2020 larger sway areas in the arms condition. When examining the PD versus NPD subgroups, PDs remained more stationary in all conditions, though the carrier caused PD participants to weight shift more often, a positive change for PDs. Conclusion: In-arms carrying altered postural sway compared with the unloaded condition, while using a baby carrier provided more similar biomechanics compared with the unloaded condition. Participants exhibited less reported pain using the baby carrier, and caregivers who develop pain during standing may find additional benefits from babywearing.