"Physicians should remain vigilant and, particularly for preterm infants, should provide SIDS prevention counseling beyond the first four months," says Donna R. Halloran, M.D., assistant professor of pediatrics at Saint Louis University School of Medicine and principal investigator.
The risk for SIDS is 50 times greater for premature infants compared to full-term infants when they are placed to sleep on their stomachs.
"Putting babies on their backs to sleep can prevent SIDS and should be discussed at the six-month visit for preterm infants. And doctors should talk to families during the traditional four-month visit, which is before the peak risk for infants of 22 to 27 weeks' gestation. It's an especially good time for SIDS preventive counseling in preterm."
The article was published in the January issue of Annals of Epidemiology.
Premature babies are at an increased risk for SIDS, which is the leading cause of post neonatal death in the United States, says Halloran, who also is a pediatrician at SSM Cardinal Glennon Children's Medical Center. Smaller babies - infants who weigh less than 10 percent of infants of the same gestational age - also have an increased risk of SIDS, she adds.
Typically, pediatricians concentrate their SIDS prevention counseling during the neonatal and two-month well-child visits. The timing works well for counseling parents of full-term babies who are at the highest risk of SIDS when they are between two and four months old. The average age of death in full-term babies occurs at 14.5 weeks.
However, Halloran's research finds that SIDS strikes very premature babies - those born at the gestational age of between 22 and 27 weeks - an estimated six weeks later than full-term infants. Preterm babies who are born at a gestational age of 28 to 32 weeks died of SIDS almost two weeks later than full-term infants, who are born at a gestational age of 40 weeks.
Premature babies usually spend the early weeks of their lives in the hospital, Halloran says.
"They are home for the same amount of time when they die of SIDS as full-term infants," she says. "This suggests SIDS has, in part, an environmental trigger."
In addition, premature infants reach the point in their physiological development when they are most susceptible to SIDS later than full-term babies, Halloran says.
Of the more than 11 million babies born in the U.S. between 1996 and 1998 in Halloran's study sample, a total of 8,199 infants died of SIDS.
SIDS rates were greatest among male children born to women who were non-Hispanic blacks or Native American; had a low level of education; were younger than 20; were unmarried; smoked; drank alcohol or had five or more previous births.
"Clinicians caring for very preterm infants need to be vigilant for longer. They must provide SIDS prevention counseling before and during peak risk, which changes with gestational length and other risk factors that may influence infant development and maturation," Halloran says.
"Mothers of preterm babies and day-care providers for these infants should stick to SIDS prevention guidelines for longer. These include placing babies on their backs to sleep, not smoking and putting babies to sleep in a safe bed of their own."
Established in 1836, Saint Louis University School of Medicine has the distinction of awarding the first M.D. degree west of the Mississippi River. Saint Louis University School of Medicine is a pioneer in geriatric medicine, organ transplantation, chronic disease prevention, cardiovascular disease, neurosciences and vaccine research, among others. The School of Medicine trains physicians and biomedical scientists, conducts medical research, and provides health services on a local, national and international level.