Moro Reflex: Characteristics And Clinical Implications In Babies
Reflexes are involuntary responses of the body to stimulation, that is, unintentional. These indicate a state of health within normality. There is a wide variety of primary reflexes, which appear at birth.
In this article We will know one of them, the reflection of the Moro, a reflex that is observed at birth, and that generally disappears after 3 or 4 months. Its persistence or absence usually indicates abnormalities or alterations in development.
Related article: “The 12 primitive reflexes of babies”
The Moro reflex, also called the “baby startle reflex,” is a primary reflex that owes its name to the Austrian pediatrician Ernst Moro, which was 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 also discovered and named it.
When does it appear?
When a baby is born, the hospital checks that he or she has some important primary reflexes, including the Moro reflex.
More’s reflection It is observed completely in newborn babies who are born after the 34th week of pregnancy, and incompletely in those born from premature birth after the 28th week.
This reflex extends until 3 or 4 months of life. Its absence or persistence may indicate neurological defects or alterations of the nervous system During the first 4 months, the pediatrician will continue to check during visits whether the child still has the reflex. Even beyond these months, because, as we will see in detail later, the persistence of the reflex beyond 4 or 5 months can indicate certain neurological defects.
What does it consist of?
To see the Moro reflex appear, the baby should be placed face up on a soft, padded surface. The baby’s head is gently lifted with sufficient support and the weight begins to be removed from the cushion; That is, the baby’s body is not lifted from the cushion, only the weight is removed. After his head is suddenly released, he drops back momentarily but it holds back quickly, not allowing it to hit the padded surface.
The normal thing then is for the baby to respond with a startled look; Her arms will move to her sides with palms facing up and thumbs flexed. The baby may even cry for a minute.
That is, Moro’s reflection appears when the baby feels a lack of support (It can also appear when there is a sudden change in position). When Moro’s reflection ends, he does it this way; The baby draws the arms towards the body, with the elbows bent, and finally relaxes.
Alterations
The absence or persistence of the Moro reflex indicates certain alterations in normal development:
1. Absence of the reflex
The absence of the Moro reflex in an infant is abnormal, and may suggest, for example, damage to the brain or spinal cord On the other hand, if it occurs only on one side, there is the possibility of a fractured clavicle or damage to the group of nerves in the brachial plexus.
If the Moro reflex persists beyond the fourth or fifth month of age, it may also indicate severe neurological defects. This is why its existence continues to be verified in pediatrician consultations.
Its phases
But what does the Moro reflex mean in the context of an integrated evaluation of the central nervous system? Let’s see first the components involved in the reflection:
Thus, the absence of these components (with the exception of crying) or an asymmetry in movements is not normal. The persistence of these components in children and adolescents is also not a good sign
On the other hand, some people with cerebral palsy may have the Moro reflex in a persistent and exacerbated manner. As we have seen, abnormalities in its manifestation indicate brain or spinal cord disorders.
Syndromes with altered reflex
Some of the syndromes with an abnormal Moro reflex are Erb-Duchenne palsy (upper brachial plexus palsy); This presents with an asymmetric Moro reflex, caused by shoulder dystocia.
Another syndrome, this time with an absent Moro reflex, is DeMorsier syndrome, which includes optic nerve dysplasia This syndrome occurs with the absence of the reflex as part of specific complications not related to the shoulder and its nerves.
Finally, the absence of the Moro reflex is also detected in newborns with Down syndrome and in neonates with perinatal listeriosis The latter consists of a rare infection, related to the ingestion of contaminated food and that can have serious consequences for the mother and the newborn.
