Acting up: Decoding infant behaviors

Pediatrician Catherine Marshall explains the reasons behind some confusing infant actions.
Startle response
Your infant has a startle response called the Moro reflex, which is a primitive neurologic reflex that’s absolutely normal. It causes baby to throw her arms out to the sides and then quickly bring them back toward the middle of her body. The reflex is present from birth and is commonly seen through baby’s fourth month, decreasing as your child gets older.
Open-eyed sleeping
Since babies spend a lot of time sleeping—and a lot of that time in REM sleep—you will undoubtedly notice your little one snoozing with her eyes open.
Rapid breathing
Babies sometimes fall into a pattern of rapid breathing followed by a period of really slow breathing. Don’t worry: Your little one isn’t in distress. What you’re seeing is a run-of-the-mill newbie behavior called periodic breathing. However, any time this behavior is associated with blueness of the mouth, or your baby goes for a period of 20 seconds or longer without taking a breath, you should call 911 immediately or head to the emergency room.
Loud bowel movements, projectile pooping and smelly gas
Completely normal (if messy and stinky), these responses are the natural result of your baby’s immature digestive system.