TUESDAY, Nov. 29 (HealthDay News) -- A new report reminds pediatricians that more young babies are sleeping on their backs, raising the risk of temporary head-flattening.

In general, the report says, the skull malformations are harmless and go away on their own, but doctors should be on the lookout for signs of serious problems.

Parents should be aware that they can prevent flattened heads on one side by coaxing babies to sleep with their head leaning to the other side, said report co-author Dr. Mark S. Dias. "Catch this early, reposition them and you can avoid a lot of grief down the road," he said.

However, it's still crucial to place babies on their backs to reduce the risk of sudden infant death syndrome (SIDS), said Dias, a neurosurgeon at the Penn State Hershey Medical Center.

Pediatricians advise parents to avoid placing babies on their stomachs to sleep, and not allow them to lay on their stomachs -- "tummy time" -- unless they're awake and being watched. Back-sleeping is thought to reduce the risk of SIDS, whose cause remains mysterious and most frequently strikes babies aged from 1 month to 1 year.

The rate of deaths from the condition has dipped since a new push for back-sleeping began in the 1990s in the United States. However, doctors have seen more cases of babies with flattened heads, Dias and colleagues reported in the December issue of Pediatrics.

A 2002 study found that 13 percent of babies born alone (not as twins or other "multiples") had signs of head flattening. Another study, published in a recent issue of the Archives of Pediatrics & Adolescent Medicine, reported that Texas saw a ninefold increase in flattened-head cases between 1999 and 2007.

When it's caused by sleeping, the condition isn't thought to be dangerous and will vanish over time, although it may take three to five years, Dias said. "It's purely cosmetic, but it can be disfiguring and the kids' heads can look funny."

The report warns that a doctor should make sure a child with a flattened head isn't suffering from craniosynostosis, a serious skull problem that may require surgery.

In normal cases caused by pressure from sleeping, surgery typically isn't required, Dias said. He added that special medical helmets may not be necessary or worthwhile either.

Instead, he said, the best approach is to be aware that babies often prefer to sleep on their backs with their heads toward one side, typically the right side. To balance things out, he said, consider putting interesting things on the other side for them to look at.

"If there's a mobile, you could put it on the other side of the crib so the baby watches that," said Dr. Bradley Thach, a professor of pediatrics at Washington University School of Medicine in St. Louis. Parents may also try switching the position of a crib if it's near a window and the baby likes to turn to one side to look outside, he said.

Dr. Roya Samuels, a pediatrician at Cohen Children's Medical Center in New Hyde Park, N.Y., provided more advice. "Parents should make sure to bring their infant for regularly scheduled well-child visits as recommended by their pediatrician so that their physician can consistently monitor the infant's head shape and head circumference," Samuels said. "The window of intervention will therefore not be missed."

More information

For more about SIDS, visit the U.S. National Library of Medicine.