Moorish reflex: characteristics and clinical implications in infants

Reflexes are the body’s involuntary responses to stimulation, that is, involuntary. These indicate a state of health in the normality. There are a variety of primary reflexes, which appear at birth.

In this article we will know one of them, the reflection of the Moor, A reflex that is observed at birth and usually disappears at 3 or 4 months. Its persistence or absence usually indicates abnormalities or alterations in development.

Related article: “The 12 primitive reflexes of babies”

Origin of the Moro reflex

Moro’s reflex, also known as a baby startle, is a primary reflex which owes its name to the Austrian pediatrician Ernst Moro, What he first described in Western medicine. Its presence in the indicated period indicates normal development in the newborn and the presence of health.

Ernst Moro (1874 – 1951) was an Austrian physician and pediatrician who studied medicine in Graz, Austria, and obtained his master’s degree in medicine in 1899. As we have seen, he not only described the Moro reflex for the first time., But found out and gave it a name.

When does it appear?

When a baby is born, the hospital exhibits important primary reflexes, including the Moorish reflex.

Moro’s reflection is fully observed in infants, Who were born after the 34th week of pregnancy, and incompletely in those born from a premature birth from the 28th week.

This reflex extends up to 3 or 4 months. Its absence or persistence may indicate neurological abnormalities or alterations in the nervous system. During the first 4 months, the pediatrician will continue to check during visits if the child still has the reflex. Even beyond these months, because, as we will see in detail below, the persistence of the reflex beyond 4 or 5 months can indicate certain neurological defects.

    That is to say?

    To see how the Moorish reflection appears, the baby should be placed face up on a soft, padded surface. The child’s head is gently lifted with sufficient support, and the weight of the pillow begins to be lifted; that is, the baby’s body does not rise from the pillow, only the weight is lifted. after his head is suddenly released, he falls momentarilyBut it holds back quickly, not allowing it to touch the padded surface.

    The normal thing then is for the baby to respond with a surprised look; his arms will move to the sides with his palms up and his thumbs flexed. The baby may even cry for a minute.

    In other words, the reflection of Moro appears when the baby feels a lack of support (It can also appear when faced with a sudden change in position). When Moro’s reflex ends, he does so; the baby retracts his arms against the body, elbows bent, and finally relaxes.


    The absence or persistence of the Moro reflex indicates certain alterations in normal development:

    1. Lack of reflex

    The absence of the Moorish reflex in a baby is abnormal and may suggest, for example, damage to the brain or spinal cord. On the other hand, if it only happens on one side, there is a risk of a broken collarbone or damage to the nerve group of the brachial plexus.

      2. Persistence of the reflex

      If the Moro reflex persists beyond the fourth or fifth month, it may also indicate serious neurological abnormalities. This is why its existence is still being verified in the consultations of the pediatrician.

      its phases

      But what does Moro’s reflection mean in the context of an integrated central nervous system assessment? Let’s see first the components involved in the reflection:

      • The reflection of fear.
      • The movement of the arms in abduction.
      • The movement of the adduction arms.
      • Usually cry.

      Thus, the absence of these components (except for crying) or asymmetry in movements is not normal. Persistence of these components in children and adolescents is also not a good sign..

      On the other hand, some people with cerebral palsy may exhibit the Moro reflex in a persistent and exacerbated manner. As we have seen, abnormalities in their manifestation indicate disorders of the brain or spinal cord.

      Syndromes with altered reflex

      Some of the syndromes with an abnormal Moro reflex are Erb-Duchenne palsy (Paralysis of the upper brachial plexus); it works with an asymmetric Moorish reflex, caused by shoulder dystocia.

      Another syndrome, this time with an absent Moro reflex, is DeMorsier syndrome, which includes dysplasia of the optic nerve. This syndrome occurs with the absence of a reflex in the context of specific complications unrelated to the shoulder and its nerves.

      Finally, the absence of the Moro reflex a is also detected. newborns with Down syndrome and newborns with perinatal listeriosis. The latter consists of an infrequent infection, linked to the ingestion of contaminated food and which can have serious consequences for both mother and child.

      Bibliographical references:

      • Garcia Madruga, JA; Deval, J. (2010). Developmental psychology I. Cognitive and linguistic development. A D. Madrid
      • MedlinePlus. (2019). Moro’s reflex. Medical Encyclopedia.
      • Paris, I. (2014). The Moorish or startle reflex in the baby. Babies and more.

      Leave a Comment