Yes, scary and exasperating though it is, this behavior is common — and perfectly normal — in babies and toddlers.
“Virtually all babies go through this phase,” says Bob Sears, a pediatrician in San Clemente, California, and the author of many parenting books, including his latest, The Vaccine Book. (He’s also the son of attachment parenting guru and pediatrician William Sears.)
Sears attributes the classic arch-and-fling to frustration and uncontrollable emotions, which can overwhelm your child’s sense of safety and control of her body.
“So even though it’s not safe for your child to launch herself backward out of your arms, she doesn’t have enough control to stop herself,” Sears says.
Many parents notice their children doing this somewhere around the nine-month mark. Sears says the trigger is emotional (“probably just the ability to become frustrated”), not physical.
With her growing perceptiveness, a 9-month-old can envision the way she wants things to be and feels angry when she doesn’t get her way. You may never figure out what prompted your child to arch. It may be something as minuscule as you handing her the wrong toy or singing her the wrong song.
Whatever the cause, you’ll want to beware when your child begins hurling herself out of your arms, and take extra care in picking up your child in midarch. “Be ready to hold on tight,” advises Sears. “You can also quickly set your baby down on a soft surface and allow her to throw herself backward on a soft carpet, pillow, or mattress.” Just be sure to stay within arm’s reach at all times.
Don’t worry — back arching is very unlikely to be a sign of a medical problem. Seizures, a rhythmic shaking of the limbs, look very different from an arch of frustration. There’s no confusing the two, says Sears.
However, back arching that occurs exclusively after your baby eats, often accompanied by gas, turning her head to the side, flexing her elbows, and extending her hips, can be a sign of gastroesophageal reflux (GERD).
This relatively rare bodily reaction is known as Sandifer’s syndrome. Sandifer’s is often mistaken for seizures. Talk to your baby’s doctor if you suspect seizures or reflux.
But if your child is like most, the back-arching sessions signal nothing more than your child’s growing independence and signify that her emotional development is right on track. So brace yourself and hang on: This won’t be the last time you’ll have to remain calm as your child’s temper flares out of control.