When Does Your Baby’s Startle Reflex Go Away?

The startle reflex, also known as the Moro reflex, is one of several reflexes normally present in infants. Learn more about what causes it and when to expect the startle reflex to go away.


The first few times I saw my daughter’s startle reflex, it was a little alarming for me. I’d also feel a little guilty whenever she did it, wondering if the cause was something  I could have easily prevented – like the time I sneezed and she nearly jumped out of her skin and promptly burst into tears, making me feel terrible and startled myself!

The truth is, however, that the startle reflex is a very normal, intuitive involuntary reflex present in all newborns and young infants. It is one of several important newborn reflexes which also include grasping, stepping, sucking and rooting.

What Causes Startle Reflex – and When Does it go Away?

Infants may startle when they feel like they are falling, are exposed to loud noises or are subjected to sudden movements. The startle reflex is actually how a baby attempts to protect herself from harm. An infant may quickly extend or flail her arms and legs, draw up her knees, clench and unclench fists, arch her back and, usually, cry before curling up again.

Doctors check the startle reflex post-delivery. It may also be observed at a few more checkups. The reflex will occur most frequently in the first month and usually will disappear by four months. By six months of age, the startle reflex should be gone as baby develops more control over his or her movements.

What the Experts Say

“Because newborn babies have limited control over their bodies, they are equipped with temporary survival skills in the form of primitive reflexes. If your newborn baby exhibits these reflexes it’s actually an indication that they are doing just fine. [These reflexes] will disappear in a few month’s time as their bodies develop and adjust.”

Dr. Buitendag, Life Fourways Hospital Pediatrician

“[These newborn reflexes] tell doctors important things about an infant’s nervous system, kind of like a system check tells you your computer is functioning correctly.”

Steven Wolf, M.D., director of pediatric epilepsy at Beth Israel Medical Center, New York City

“It’s a little like she’s saying, ‘Time out. I need some help here!’ This is how she communicates her needs.”

Carole Kenner, associate dean of academic advancement at the University of Illinois at Chicago’s College of Nursing


When to Call Your Doctor

Concerned about your baby’s startle reflex? Issues are usually caught by your baby’s doctor. But if you notice the reflex is lacking on one side of baby’s body, this may be a sign of a nerve injury or a broken shoulder. If the reflex is not present on both sides, this may be indicative of spinal cord or brain damage.

However, if you haven’t noticed your baby’s startle reflex, this is not necessarily a cause for concern. Be sure to schedule an appointment with your doctor to determine if the startle reflex in your infant is present and normal. If your doctor is concerned, he or she will conduct additional testing.

Some parents may also be afraid their babies are experiencing seizures when they are exhibiting the startle reflex. “The Moro reflex lasts for only a few seconds; a seizure usually continues for a good deal longer,” says Dr. Tanya Rember Altmann, A Westlake Village, California pediatrician.

How to Avoid Startling Your Baby

Can’t stand to see your baby startled? Here are a few ideas to try.

  • When lowering baby into crib or bassinet, hold your baby close and only release your child after his or her back is touching the mattress so as not to initiate a falling sensation.
  • Swaddling may also help your baby feel safe. Some babies feel safer when they are held close.

“A newborn who startles easily and often might be comforted by the security of being bundled or swaddled in a tight blanket,” says Kenner. This is because swaddling acts in place of the snug and comfy closeness your baby felt while living in the womb.

However, there is a right and wrong way to swaddle, and there is also some controversy about swaddling safety. If you’re nervous about the practice, Dr. Sears offers these alternatives to baby swaddling. Though he does not put down the practice, Dr. Sears suggests swaddling only up until a certain age and does not recommend doing it overnight.

  • Get your baby moving. Make time for movement. Helping your child strengthen his or her muscles and allowing space for those little arms and legs to stretch out will help speed along the process of eliminating the startle reflex.
  • Settle baby with motion. Most babies enjoy rocking motions that will often cause them to drift off to sleep. Snuggle baby in a rocking chair, rock your little one back and forth gently in a cradle, or take a drive in the car (make sure to take your baby out of the car seat and put her to bed after she falls asleep).

Rhonda Mix

Rhonda is mom to a bright and sweet little girl. She enjoys writing for work, writing for fun and reading when time allows. Also passionate about travel, she has a fondness for Taiwan - where she once lived in a previous chapter of her life. She looks forward to all the adventures ahead and exploring new places with two of her biggest loves - her daughter and husband.

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