What action should a nurse take to elicit a newborn's Moro reflex?

To elicit a newborn's Moro reflex, striking the surface of the crib on which the newborn is resting is an effective method. The Moro reflex, also known as the startle reflex, is a primitive reflex that occurs when an infant perceives a sudden loss of support or a loud noise. When the crib surface is struck, it creates a sudden vibration and sound, triggering the infant's reflex response. This typically results in the newborn splaying out their arms and legs in a startled manner and then pulling them back in, which is characteristic of the Moro reflex.

Other methods mentioned, such as gently lifting the newborn off the surface, holding the newborn upright, or rubbing the abdomen lightly, do not specifically cause the sensation or environment needed to properly elicit the Moro reflex. Therefore, striking the crib is the most direct and appropriate action to activate this reflex in a newborn.