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Babywearing Summary Statement: Babywearing is becoming increasingly popular along with the growing interest in Attachment Parenting. Proper infant hip position while babywearing is especially important because the period of time for babywearing is usually longer than baby transport. For information about baby transport, please refer to the IHDI Educational Statement regarding baby carriers, and swaddling. When proper hip position is maintained while babywearing, there may be substantial benefit for natural hip development. The M-position is a natural clinging position for infants – also known as the Spread-Squat, or Jockey Position. This is recommended as a healthy habit with the thighs spread around the mother’s torso and the hips bent so the knees are slightly higher than the buttocks with the thighs supported. This practice may decrease the risk of hip dysplasia, and should be encouraged in regions with high prevalence of hip dysplasia especially where screening and treatment are insufficient.
Hip-healthy positions with thighs flexed, supported and spread apart. Less spread with more flexion is healthy, as is slightly more spread with less flexion as the child grows.
Inward-Facing vs Outward-Facing Infant Carrying
Summary: Inward-Facing Carrying may be healthier for hip development, especially during the first six months if infancy. For this reason, the IHDI recommends inward-facing during this period of rapid hip development. During the second six months of life the hips are developing more slowly, but there may be additional benefit for inward-carrying until age one year.
Background: While attainment of head control is often used as a milestone that allows for outward-facing infant carrying, the hips are still developing rapidly until age six months, and more slowly during the next six months. When the infant is carried while facing towards the mother, an infant may grasp the mother’s torso by using the inner thigh muscles. This generates beneficial forces for hip development while the infant is in the M-position. Therefore, the International Hip Dysplasia Institute recommends inward-facing carrying for the first six-months of infancy to promote optimum hip development. While outward-facing may not be harmful, the inward-facing position is acknowledged as hip healthy.
Many babywearing consultants also recommend heart-to-heart (inward-facing) positioning along with clear visibility of the mother’s face instead of facing the outside world. Infants play peek-a-boo because they don’t know where the adult goes when the adult is not immediately visible. Young infants take comfort and cues from seeing the parent’s face instead of facing the outside world alone. This changes with age, but behavioral specialists often recommend inward-facing for the first year of life. Unpublished biomechanical studies show that inward-facing is more ergonomic for the adult carrying the child because it places the infant’s center of gravity closer to that of the adult. When infants are carried in arms, it becomes apparent that the clinging child facing towards the parent is much easier to carry than the child held in a sitting position facing away from the parent.
The inward-facing position has been identified as the natural position assumed by infants and mothers during carrying. The newborn infant has grasp reflexes that suggest clinging is a natural behavior. When lifted while supported underneath the arms, the young infant will instinctively bend the hips and knees and spread the thighs in preparation for being placed on the mother’s body. This natural and instinctive infant leg positioning exactly matches the average measurements of the torso of women of child-bearing age. (Kirkilionis E, Zool. Jb. Physiol. 1992;96:395-415) The waist-to-hip ratio of females may also facilitate hip sitting position for infant carrying. During unassisted side-carrying, the mother assumes an asymmetrical posture by shifting her waist and trunk to increase sitting support and to decrease work effort. In addition, the wider flare of the pelvis of the female may represent an adaptation to parent-clinging behavior because the female pelvis has greater flare and width of the iliac crests. This is unrelated to the larger and rounder area inside the female pelvis that accommodate pregnancy and childbirth. These findings represent a possible adaptation of the mother and infant for inward carrying, especially when the infant is resting on the side of the mother’s torso while supported by the flare of the pelvis. These instinctive and anatomical characteristics of humans, suggest that humans are a parent-clinging species similar to other primates. (Büschelberger, PhD Thesis, Dresden 1961 https://hipdysplasia.org/wp-content/uploads/2020/06/Buschelberger-English-with-images-Final.pdf)
Research in the 1950s showed the harmful effects of traditional swaddling and the beneficial effects of babywearing for prevention and treatment of hip dysplasia.
As many as one in six newborn babies have mild hip instability at birth, and approximately one per thousand has a dislocated hip. Babies with increased risk include those with one or more of the following: a family history of hip dysplasia, breech position, first born, female gender, prolonged labor and larger babies. However, newborn hip instability is only part of the problem. A study from Norway reported that 90% of young adult hip joint replacements for dysplasia were never diagnosed as dysplasia during infancy. This suggests that milder types of hip dysplasia are often undetected, or that hip development is abnormal for most people with adult hip dysplasia. Some evidence from Austria suggests that healthy hip positioning during early infancy may decrease the risk this type of adult hip arthritis.3
Cultures where babywearing is common have a low frequency of hip dislocations in babies. Whether this is due to the M-carrying position or to genetics is unproven. However, this low frequency is in sharp contrast to high rates of hip dislocation where traditional swaddling is practiced with the hips and knees held straight during early infancy.5
When baby wearing is practiced with each hip in approximately 40° to 55° of abduction and 90° to 110° of flexion, the femoral head – the ball of the hip joint – is pressed evenly into the center of the hip socket. Some variation from this position also maintains the hip in the center of the socket. When the hips are flexed, or bent up more, then less spread is needed. When the hips are straighter, then more spread helps maintain the healthy position. This has been called the “cone of stability.”
Muscle action of the infant further presses the ball into the socket as the infant moves and clings to the mother.6 This type of muscle activity is beneficial for healthy joint development. 7,8
A recent scientific report has provided additional information that back-carrying may decrease the risk of hip dysplasia in Malawi.4 Although this is still controversial, the International Hip Dysplasia Institute supports the conclusion of the authors, who stated, “If a carrying position of infants during early months of development can reduce the incidence of DDH, then a public health initiative promoting back-carrying could have significant world health and financial implications in the future management of DDH and also have potentially huge effects on the timing and severity of development of adult hip arthritis.”
The International Hip Dysplasia Institute supports proper babywearing with the hips in the M-position as a method to encourage healthy hip development.
- Sewell M, Eastwood DM. Screening and treatment in developmental dysplasia of the hip – where do we go from here? Intl. Orthop. 2011;35(9):1359-1367.
- Engesaeter I, Lie SA, Lehmann TG, Furnes O, Vollset SE, Engesaeter LB,. Neonatal hip instability and risk of total hip replacement in young adulthood. Acta. Orthop. 2008;79:321-326.
- Thallinger C, Pospischill R, Ganger R, et al. Long-term results of a nationwide general ultrasound screening system for developmental disorders of the hip: the Austrian hip screening program. J. Child Orthop 2014; 8:3-10
- Graham S, Manara J, Chokotho L, Harrison WJ. Back-carrying infants to prevent developmental hip dysplasia ans its sequelae: is a new public health initiative needed? J. Pediatr. Orthop. 2015;35(1):57-61.
- Mahan S, Kasser JR. Does swaddling influence developmental dysplasia of the hip? Pediatrics. 2008;121:177-178.
- Fettweis E. Muscle-mechanical and biomechanical conditions of the squat-seat position in the treatment of infantile dislocation of the hip.[German] Orthop. Praxis. 1991;8 19/91:474-481.
- Heegaard J, Beaupre GS, Carter DR Mechanically modulated cartilage growth may regulate joint surface morphogenesis. J Orthop Res. 1999;17:509-517.
Zuscik M, Hilton JM, Zhang X, Chen D, O’Keef RJ. Regulation of chondrogenesis and chondrocyte differentiation by stress. J Clin Invest. 2008;118(2):429-438.