Moro reflex - Definition

The Moro reflex, also known as the infant startle reflex, is one of the infantile reflexes. It may be observed in incomplete form in premature birth after the 28th week of gestation, and is usually present in complete form by week 34 (third trimester). It is normally lost by the 6th month of life postpartum.

The primary significance of this reflex is in evaluating integration of the central nervous system (CNS), since the reflex involves 4 distinct components:

1. Startle
2. Abduction (spreading out the arms)
3. Adduction
4. Crying (usually)

Absence of any component (except crying) or any asymmetry in the movements is abnormal, as is persistence of the reflex in older infants, children and adults.

External links

• Medline Plus (http://medlineplus.gov/): Moro reflex (http://www.nlm.nih.gov/medlineplus/ency/article/003293.htm)