Why does my newborn startle so easily?

Until he's 2 months old, he may respond to loud noises, sudden movement, or changes in temperature (such as when you remove his diaper) by throwing his hands out to the sides and his feet up in the air and opening his eyes wide. This normal response to a new or uncomfortable sensation is called the Moro reflex. The Moro reflex tells us that a baby's nervous system is healthy and functioning normally.