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Longer SIDS Risk for Premature Babies

Sudden Infant Death Syndrome Strikes Later for Premature and Small Babies
WebMD Health News
Reviewed by Louise Chang, MD

Feb. 7, 2006 -- Premature babies may be at risk for SIDS (sudden infant death syndrome) longer than full-term babies, a new study shows.

SIDS is the sudden, unexpected death of a baby less than 1 year old with no explanation from a thorough investigation.

The new study, published in the Annals of Epidemiology, shows:

  • Premature babies died of SIDS up to six weeks later than full-term babies, on average.
  • Babies born small for their gestational age had a higher SIDS risk than appropriate-sized infants.

The researchers included Donna Halloran, MD, MSPH. She worked on the study while a pediatrician at the University of Alabama. Halloran is now an assistant professor of pediatrics at Saint Louis University's medical school.

Doctors "must remain vigilant and, particularly for preterm infants, should provide SIDS prevention counseling beyond the first six months," Halloran and colleagues write.

SIDS and Premature Babies

Data came from U.S. birth and death records from 1996 to 1998. Nearly 11.4 million babies were born in the U.S. during that time. SIDS killed 8,199 of those babies, the study shows.

Premature babies typically died of SIDS later than full-term babies. Here are the babies' average ages when SIDS struck:

  • Full-term babies: 14 weeks after birth
  • Premature babies born at 28-32 weeks: 15 weeks after birth
  • Very premature babies born at 22-27 weeks: 20 weeks after birth

The average age at SIDS death was similar for babies born slightly prematurely (at 32-38 weeks of gestation) and full-term babies.

SIDS deaths were most common among babies born to women who were black or Native American, had low levels of education, were younger than 20, were unmarried, had five or more previous births, smoked, or drank alcohol. SIDS rates were also higher for baby boys, premature babies, and infants born small for their gestational age.

SIDS and Small Babies

The researchers checked the babies' size -- particularly, whether babies who died of SIDS were bigger, smaller, or average in size for their gestational age.

Babies who were small for their gestational age were 1.7 times more likely to die of SIDS than babies of average size for their gestational age. The timing of those SIDS deaths didn't differ much.

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