If your new baby is startled by a loud noise, a sudden movement, or feels like he’s falling, he might respond in a particular way. He might cry and suddenly extend his arms and legs, arch his back, and then curl everything in again.

This is an involuntary startle response called the Moro reflex. Your baby does this intuitively in response to being startled. It’s something that even newborn babies do.

Your baby’s doctor will check for this response during the post-delivery exam and at the first few scheduled checkups.

Newborn Reflexes

Babies are born with a number of reflexes. Soon after birth, they can show reflexes for rooting, sucking, grasping, and stepping, among others.

  • Rooting. If you gently touch his cheek, your baby will turn his face, mouth open, toward your hand or breast. Babies do this instinctively to find food.
  • Sucking. Your baby will automatically begin sucking if something touches the roof of his mouth. Babies do this instinctively for nourishment. But although your baby naturally knows how to suck, it can take some practice to turn it into a skill. If you’re having a hard time breast-feeding, don’t be discouraged. Instead, ask for help from a lactation consultant. You can find one through your local community hospital.
  • Grasping. Your baby will close his fingers around something pressed into his hand, like your finger or a toy. This reflex helps babies develop the skills to intentionally grasp things as they grow.
  • Stepping. If you hold your baby upright and let his feet touch a flat surface, he’ll pick up one foot and then the other. It looks as though he’s trying to take steps. This reflex helps babies develop the controlled skill of walking, which he’ll probably start doing around his 1st birthday.

These reflexes are a normal part of a baby’s development. They help your baby function in the world. The Moro reflex is another normal baby reflex.

How Can I Keep My Infant from Getting Startled?

You may notice your baby’s startle reflex when you’re trying to put him down to sleep. Leaning over to lay him down may give your baby the sensation of falling, and it can wake your baby even if he’s sleeping soundly.

If you’re frustrated by your baby’s Moro reflex because it’s keeping him from sleeping properly, try these tips:

  • Keep your baby as close to your body for as long as possible when you lower him into his crib or bassinet. Gently release your baby only after his back is touching the mattress. That support should be enough to prevent him from experiencing a falling sensation, which can trigger the startle reflex.
  • Swaddle your baby to make him feel safe and secure. Swaddling is a technique that mimics the close, cozy quarters of the womb. It can also help your baby sleep longer.

How to Swaddle

To swaddle a baby, use a large, thin blanket. Lay the blanket out on a flat surface, and fold one corner in slightly. Gently lay your baby faceup on the blanket with his head at the edge of the folded corner. Bring one corner of the blanket across your baby’s body and tuck it snugly beneath him. Fold up the bottom piece of the blanket, leaving room for your baby’s feet and legs to move. Bring the last corner of the blanket across your baby’s body and tuck it beneath him. This will leave only his head and neck exposed.

A swaddled baby should only be laid on his back to sleep, and you should check regularly to be sure your baby doesn’t overheat. If you have questions about swaddling, ask your doctor.

Encouraging Movement

Your baby’s startle reflexes will begin to disappear as he grows. By the time your baby is 3 to 6 months old, he probably won’t demonstrate the Moro reflex any longer. He’ll have more control over his movements, and his reflexes will become less jerky.

You can help your baby progress by making time every day for movement. Give your baby space to stretch his arms and legs. This will help him tone and strengthen his muscles. Even newborn babies should have the opportunity to move, including their little heads. Just be careful to provide support to your baby’s head and neck when you’re holding him.

When to Call Your Doctor

When a baby doesn’t have normal reflexes, it can be sign of potential problems. If the Moro reflex is lacking on one side of your baby’s body, it can be the result of a broken shoulder or a nerve injury. If the reflex is lacking on both sides, it might suggest brain or spinal cord damage.

Don’t be overly concerned if you haven’t noticed your baby’s startle reflex. Your doctor will be able to determine whether your baby’s Moro reflex is present and normal. If he has any concerns, further testing may be necessary to examine your baby’s muscles and nerves.