Washington, Jul 9 (IANS): Nearly half of the newborns develop flat spots on their heads by the time they are two-month old due to sleeping on their backs to prevent sudden infant death syndrome, a new Canadian study has found.

Published in the US journal Paediatrics, the study investigated the occurrence of positional plagiocephaly, or flat spots on heads, in infants 7 -12 weeks of age who attend a two-month well-child clinic in Calgary, Alberta, Canada, Xinhua reported.

Researchers from the Canadian Mount Royal University assessed 440 healthy full-term infants who had been born at more than 37 weeks of pregnancy.

Of these infants, 205, or more than 46 per cent, were observed to have some form of flat spots on their heads. Of all infants with the condition, about 63 per cent had flattening on the right side and about 78 per cent had a mild form of the condition, they said.

"Since the 1992 recommendation from the American Academy of Pediatrics to have infants sleep on their backs, infant mortality from sudden infant death syndrome has declined dramatically," the researchers said in a statement. "One consequence, however, has been an increase in positional plagiocephaly, or flat spots on infants' heads."

According to the researchers, the high rate of head flattening indicates that parents should be educated early about how to prevent the condition from occurring.

Flat spots, however, are generally harmless. The researchers said there is some indication that children with positional plagiocephaly have mild developmental delays, but that those typically disappear by 18 months.

Treatment for the condition is usually simple and painless, often cured by repositioning the infants while they sleep, encouraging them to alternate their head position while sleeping on their backs.

The American Academy of Pediatrics does not recommend using any wedge pillows or other devices to keep babies in one position, and only kids with severe cases may need to wear a special orthotic helmet.