The health concern: Plagiocephaly (pronounced play-jee-uh-sef-uh-lee), also known as flattened head. Basically, it's a persistent flat spot that develops on a baby's head, either on the back or on one side.

Why it's in the news: Earlier this month, Pediatrics, the journal of the American Academy of Pediatrics, published a study showing that placing children on their backs to sleep -- long lauded as a way to help prevent Sudden Infant Death Syndrome -- might be leading to a higher incidence of flattened heads. The study looked at 440 healthy, full-term infants ages 7 to 12 weeks and found that 46.6 percent of them had plagiocephaly. Of those, about 63 percent had flat spots on the right side.

Locally, doctors said the incidence of flattened head depicted in the study is consistent with what they see. "We've been seeing more of it recently," said Dr. Robert Chessin, pediatrician with Pediatric Healthcare Associates, with offices in Bridgeport, Fairfield, Shelton, Stratford and Trumbull. He said health experts actually used to think sleeping on their backs was bad for babies, because of fears that they would suffocate if they spit up while sleeping. That eventually was determined to not be true.

In 1992, the Academy of Pediatrics began recommending back or side sleeping to help prevent Sudden Infant Death Syndrome, and many credit that recommendation with a 50 percent decrease in SIDS. However, many doctors said sleeping on one side or the back can make infants more likely to develop flat spots on their heads as their skulls mature. "The head grows very rapidly over the first few months of life, but it won't grow against a fixed point of resistance, like a mattress," said Dr. Gerald Rakos, chairman of the department of pediatrics at Stamford Hospital.

Should you worry?: "The good news is that there aren't any good studies to show that there are any issues with (flatness of the head) other than cosmetic," Rakos said.

Indeed, the Pediatrics study showed about 78 percent of the babies they saw with plagiocephaly had a mild form of it that could be corrected with nonsurgical treatments.

But doctors cautioned that flatness of the head is still something to be aware of. Chessin said, in some cases, it can be caused by craniosynostosis, a serious skull abnormality that happens when sutures -- joints in the baby's skull -- close too soon. This can lead to skull deformity and neurologic damage.

Unlike craniosynostosis, plagiocephaly caused by sleeping in a certain position doesn't generally affect the baby's brain, Chessin said. He agreed that flatness of the head is mostly a cosmetic problem, but it is one most parents will want to fix. "Babies can look very odd," Chessin said.

Fortunately, experts said, most cases of head flatness can be corrected with physical therapy, helmets and other nonsurgical treatment. It's also relatively easy to prevent. Babies should still sleep on their backs or sides to lower SIDS risks, but there are ways to keep babies from favoring a certain side. Chessin recommended hanging a mobile on the side of the crib opposite from the side the baby sleeps on, so the child will have to turn his or her head to look at it. Other suggestions include changing the direction the baby lies in the crib from week to week, which will encourage the child to turn his or her head in different directions. One major way to prevent head flatness is by promoting "tummy time," while the baby is awake and supervised. "Babies should be spending some time on their bellies, especially when they get older," said Dr. Robert Herzlinger, Bridgeport Hospital director of neonatology.

Keeping an eye on your baby's positioning can help his or her skull develop properly. "You want your babies to have nice round heads," Chessin said.; 203-330-6290;;