It's a word long enough to strike fear into the hearts of mothers everywhere.
But pediatricians offer encouraging news for the most part - it's usually only a temporary flattened-head condition that infants get while avoiding the much more serious risks of sudden infant death syndrome.
SIDS is rightly feared. And physicians agree with the American Academy of Pediatrics' 1990s directive to let babies sleep on their backs.
That strategy, which may have reduced the incidence of SIDS by more than 40 percent over the past 14 years, does have a cosmetically negative effect if steps are not taken to counter it.
An infant's head, designed with the capability of allowing for very rapid brain growth during the first two years of life, is malleable. Not exactly like clay, but given daily pressure over time, it can be shaped.
When a baby spends enough time lying flat, a flatness to the back of the head can develop. This is positional plagiocephaly.
"Incidence of deformational plagiocephaly has been estimated to be as low as one in 300 live births to as high as 48 percent of typical, healthy infants younger than 1 year, depending on the sensitivity of the criteria used to make the diagnosis," the organization stated in its Volume 112, No. 1, July 2003, report.
According to Dr. Richard Lampe, chairman of the department of pediatrics at Texas Tech University Health Sciences Center, a flattened or asymmetrical head can be caused by multiple factors, not just sleeping on the back.
"As babies are in utero - in the mother's womb - there can be some pressures and some positional ones that might make the baby's head have this positional shape as the baby comes out," he said.
Dr. Patricia Evans, who practices pediatrics with an emphasis on neurology, also alludes to prebirth conditions that can influence the shape of a baby's head.
Back to sleep
"One category probably that leads the list is the back-to-sleep program that was instituted in 1992 by the American Academy of Pediatrics," he said. "It has reduced the overall amount of SIDS by babies sleeping on their backs by about 40 percent. But with that it has also been noted that when babies spend their time on their back, they can get these positional skull deformities - the backs of their heads will be a little bit flatter."
Another cause of flattened heads can involve the extended use of infant carriers outside a motor vehicle.
"Babies need to sleep on their backs to prevent SIDS, and they certainly need to travel in their car seats," Evans said.
"But for a child to be parked in an infant seat just because there's no place to put them ... if they spend most of the hours of the day that way, then their head can flatten."
Starting with the neck
Unusually stiff neck muscles also can be a contributing factor in misshapen heads, and alert pediatricians also check for that possibility. It is a condition known as torticollis. According to Lampe, it is similar to an awry neck in adults, in which the neck is twisted a bit in one direction.
Those babies, he said, sometimes have sustained a degree of stretching to their neck when they come through the birth canal, and they may experience a small amount of bleeding into the neck muscle.
It can be serious if not treated. Flatness can develop on one side of the head for torticollis babies. As the head develops, one ear can become positioned closer to the face, and one side of the face appears flatter than the other.
About the brain
Lampe said the most serious cause of head deformity is represented by a category in which the baby's skull bones are prematurely closed.
"The lines between these bones are called sutures," he said. "Those sutures need to be open to allow the brain growth."
Surgery is necessary to prevent the condition from affecting the brain's development.