Randomized Clinical Trial Investigating the Developmental Effects of Two Different Methods of Neonatal Positioning in the NICU

Infants born prematurely have a high risk of developmental impairment. Subsequently, preterm infants are often seen by therapy services in the neonatal intensive care unit and are often recommended for early intervention services at discharge. One of the earliest interventions for preterm infants in the Neonatal Intensive Care Unit (NICU) is positioning, as altered positioning can have a significant impact on later function.

Preterm infants have a positioning disadvantage from early on in their development. The final trimester of pregnancy promotes the flexed position, when the infant is crowded by the uterine environment and experiences rapid brain growth, mediating flexion and midline orientation. When infants are born too soon, they miss the in utero flexion positioning. They lack the central nervous system maturity to enable flexion and do not have the tone and strength for movement against gravity. In addition, preterm infants are confronted with altered sensory experiences, resulting from static, extended positioning and environmental factors associated with life and medical interventions outside the womb. Therefore, early transition to the extrauterine environment is a challenge for premature infants, as they face overwhelming sensory stimuli that their bodies are not yet prepared to process.

It has been demonstrated that the positioning of the preterm infant differs from that of a full term infant. The tightly flexed positioning of a full term newborn is called physiological flexion. It involves symmetrical flexion of the extremities, shoulder protraction, and posterior pelvic tilt.

Physiological flexion has developmental importance. This positioning enables infants to remain motorically and physiologically organized and facilitates self-soothing and self-regulation behaviors, such as sucking and hand to mouth contact. The flexed position provides the infant with a sense of containment and security, which mimics the intrauterine environment. In addition, physiological flexion is associated with greater extremity contact with the trunk, which imitates the womb and gives infants sensory feedback.

The benefits of early physiological flexion can have long term benefits on development. Many neonatal reflexes, such as upper and lower extremity recoil, palmar and plantar grasp, and pull to sit are mediated by flexion response. These early flexion responses form the foundation for later movement acquisition. Physiological flexion also promotes later development of normal balance and posture. Ideal posture supports the development of head control, sitting, crawling, walking, transferring from one position to another, and manipulating objects. Due to missing the third trimester, preterm infants are at risk for assuming suboptimal positions, thus missing the early benefits of physiological flexion.