Moro reflex

Your baby's health care provider will check for this reflex right after birth and during well-child visits.

To see the Moro reflex, the child will be placed face up on a soft, padded surface.

The head is gently lifted with enough support to just begin to remove the body weight from the pad. (Note: The infant's body should not be lifted off the pad, only the weight removed.)

The head is then released suddenly, allowed to fall backward for a moment, but quickly supported again (not allowed to bang on the padding).

The normal response is for the baby to have a startled look. The baby's arms should move sideways with the palms up and the thumbs flexed. The baby may cry for a minute.

As the reflex ends, the infant draws its arms back to the body, elbows flexed, and then relaxes.

This is a normal reflex present in newborn infants.

Absence of the Moro reflex in an infant is abnormal.

• Absence on both sides suggests damage to the brain or spinal cord.
• Absence on only one side suggests either a broken shoulder bone or an injury to the group of nerves that run from the lower neck and upper shoulder area into the arm may be present (these nerves are called brachial plexus).

A Moro reflex in an older infant, child, or adult is abnormal.

An abnormal Moro reflex is most often discovered by your provider. Your provider will perform a physical exam and ask about the child's medical history. Medical history questions may include:

• History of the labor and birth
• Detailed family history
• Other symptoms

If the reflex is absent or abnormal, further tests may need to be done to examine the child's muscles and nerves. Diagnostic tests, in cases of decreased or absent reflex, may include:

• Shoulder x-ray
• Tests for disorders associated with brachial plexus injury

Startle response; Startle reflex; Embrace reflex

Edelman HE, Stratton MJ. Neurology. In: Anderson CC, Kapoor S, Mark TE, eds. Harriet Lane Handbook, The. 23rd ed. Philadelphia, PA: Elsevier; 2024:chap 20.

Holler-Managan YF. Neurologic evaluation. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 630.

Volpe JJ, El-Dib M. Neurological examination: normal and abnormal features. In: Volpe JJ, ed. Volpe's Neurology of the Newborn. 7th ed. Philadelphia, PA: Elsevier; 2025:chap 12.

Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.