Moro Reflex

What is the Moro reflex?

The Moro reflex is a newborn reflex babies have when they’re born. It’s an automatic response they show when they feel like they’re falling or something startles them. It’s also the reflex that makes babies take their first breath. It’s named for a German pediatrician, Ernst Moro, who described it first in 1918.

You may notice the Moro reflex yourself, especially when you lay your baby down on their back (like for sleeping). It makes your baby do the following:

• Spread and extend their arms
• Fan out their fingers and thumbs
• Throw their head back
• Cry

Healthcare providers look for the Moro reflex as part of a standard newborn assessment after birth. That’s because it’s a reliable indicator of how well a newborn’s nervous system works. They’ll also use it when checking a baby’s nervous system or looking for certain medical conditions.

How do I check the Moro reflex in my newborn?

You can check your baby’s Moro reflex by creating the feeling of falling. One way to do that is by holding your baby in your hands (with their head supported) and quickly lowering them. That simulates the feeling of falling while still keeping their body and head supported.

If your baby has a normal Moro reflex, they’ll have a startled look on their face. They’ll extend their arms sideways with their palms up and their thumbs flexed. Your baby may also cry. When you support your baby’s head again, they’ll bring their arms back into their body, flex their elbows and relax.

Why do babies have the Moro reflex?

The Moro reflex is protective. Babies can’t deliberately ask for help or call out if they feel like they’re going to fall. That’s why the reflex does it all automatically.

The Moro reflex happens when your baby’s vestibular system detects the feeling of falling. That makes it send emergency signals to your baby’s brainstem, activating the reflex.

Fetuses can have the Moro reflex as early as the second trimester but usually don’t until the third trimester. Babies typically don’t have the reflex past 6 months old.

Usually, the Moro reflex shifts gradually into another startle reflex, the Strauss reflex. That reflex stays in place for the rest of your life. The Strauss reflex makes you jump or flinch and then evaluate whether you’re in danger.

Is the Moro reflex the same thing as the startle reflex?

Yes and no. There’s more than one startle reflex. The Moro reflex is the one that newborns have. But by the time they reach 6 months old, it should change to the Strauss reflex.

What conditions could my baby’s pediatrician be looking for using this reflex?

Healthcare providers, like pediatricians, look for the Moro reflex to make sure your baby’s nervous system works correctly. They can also use it when diagnosing or ruling out issues like:

• Birth injuries
• Congenital myopathy
• Infantile spasms

Your provider will watch for a few key factors when checking this reflex:

• The strength of the reflex. A weaker reflex can happen normally, like in babies born preterm. But it can also indicate something disrupting your baby’s central nervous system.
• The symmetry of the reflex. The Moro reflex should be symmetrical, meaning it affects both sides (left and right) evenly. If it isn’t symmetrical, it could indicate an injury or a nerve disease.
• How it relates to your baby’s age. The reflex is usually weaker in preterm babies but gets stronger. But by the time they reach 6 months, it should fully convert to the Strauss reflex. If it doesn’t convert, it could signal developmental delays or other issues.

What happens if my child still has a Moro reflex after they pass 6 months old?

If your baby still has a Moro reflex once they reach 6 months old, you should talk about it with their pediatrician. It might mean your baby’s nervous system is working differently than expected. Babies who still have a Moro reflex past 6 months old may be:

• Overly sensitive to startling sounds or events
• Anxious
• Hyperactive

If this is the case for your baby, there are treatments that might help. These focus on using specific exercises that train your baby’s nervous system to react more like it should. Your baby’s pediatrician can tell you more about them and offer recommendations.