Moro Reflex

Issues of Concern

The Moro reflex is particularly weak in preterm newborns because of lower muscle tone, inadequate resistance to passive movements and slow arm recoil, compared with those of full-term newborns at the same post-conceptual age.[4] The absence of the Moro reflex during the neonatal period and early infancy is highly diagnostic, indicating a variety of compromised conditions.[3] 

Clinical Significance

The absence or premature disappearance of the Moro reflex can result from a birth injury, severe asphyxia during the birthing process, intracranial hemorrhage, infection, brain malformation, general muscular weakness of any cause, and cerebral palsy of the spastic type.[5][1] Asymmetrical Moro can be due to a local injury. Damage to a peripheral nerve, cervical cord, or a fracture of the clavicle are common causes to an asymmetric Moro and causes inhibition of the reflex on the affected side.[3][6] Prolonged retention of the Moro reflex can also be a sign of spastic cerebral palsy.[5] 

In one study, the presence or absence of the Moro reflex is more related to the development of the infant and less likely pertains to pathogenic conditions.[4] Another study showed a clear association between retained primitive reflexes and delay in motor development in very low birth weight infants.[7] Training on how to perform moro reflex correctly among healthcare workers is important and can improve the yield of the physical examination.[8]

Nursing, Allied Health, and Interprofessional Team Interventions

The Moro reflex is a normal reaction to stimuli of an infant, and it is essential for the entire healthcare team to understand what a normal reaction looks like and when to be concerned. Often families will have questions and concerns about their developing child. While a physician can comfort and address concerns, it is often the front line nursing staff in the hospital or a clinic environment that are first available to address parental concerns and recognize concerning finding. Identifying abnormalities early can then lead to the inclusion of physical therapy, occupational therapy, neurology, and developmental specialist into the care of a child.

It is crucial to the entire interprofessional team, including the nurses, recognize that an asymmetric Moro reflex at birth can be indicative of neuronal damage or a clavicular fracture.[6] Also, it is necessary to remember that the Moro reflex should disappear by six months of life and a retained reflex should raise suspicion for gross motor delay and possible spastic cerebral palsy.[5][7]