It's one of the great success stories of public health. The number of children dying from Sudden Infant Death Syndrome has plummeted in recent years after pediatricians began encouraging parents to put babies to sleep on their backs.
But the so-called "Back to Sleep" campaign has had an unintended consequence - more children are now developing "flat-head syndrome," a condition medically known as deformational plagiocephaly. Apparently spending so much time in one position can flatten the back of an infant' soft, malleable skull.
And a new study, published this week in the journal Pediatrics, has found a link between flat-head syndrome and a delay in the development of certain motor skills.
The researchers tested 472 babies, half with the condition and half without. The average age was six months. The results revealed that about 25 per cent of tots with flat head syndrome had less developed motors skills - such as the ability to grasp objects or roll over - than the other children.
"Our study is one of the first to fairly conclusively find that, in the first year of life, there are developmental delays among children having deformational plagiocephaly," said the lead researcher Matthew Speltz at Seattle Children's Hospital.
"These may be very temporary and short-lived delays that, on their own, go away. So we don't want to alarm parents at this point," he said, adding that the researchers plan to monitor the children for several years.
He also stressed that parents should continue to put babies to sleep on their backs. "There is no doubt that the supine position has reduced the number of infant deaths dramatically," he said. "It is better to have a baby who is alive - delays in motor skills can be corrected."
The researchers can't yet explain their findings. But Dr. Speltz doesn't think that the flattening of the skull is actually affecting brain development. Instead, he believes that when some infants are placed on their backs, they are less likely to move around. And that means they are not as likely to acquire motor skills. Based on this interpretation, flat-head syndrome is simply a indicator of a child who is too immobile.
The problem may be corrected with more "tummy time," speculated Dr. Speltz. When babies are awake and can be supervised, they should be frequently placed on their bellies to play, he said. In this prone position, "they have to use their arms and hands to support themselves, they tend to role around more and they have to hold up their heads to look around," he explained. In other words, they are encouraged to develop motor skills.
"We don't want to change the Back to Sleep recommendation," he said. "But we may need to help babies with flat heads be more active."