Unraveling the riddle of Sudden Infant Death Syndrome

MILLBRAE, Calif. - Magali Leialoha has relived countless times that moment on May 6, 2005, when she tickled her 3-day-old son's feet and patted his head, and the infant didn't respond. Five minutes earlier, Kai had been breastfeeding. Now he was dead.

For the first time in public, the 41-year-old Burlingame, Calif., mother recently shared her agonizing experience at the state's 27th annual conference on Sudden Infant Death Syndrome, or SIDS.

More than 130 SIDS parents and public health nurses who provide SIDS counseling gathered for the conference to learn about the latest research advances on SIDS, as well as ways of easing the grief and guilt that burden parents of infants who died from SIDS.

Virtually every parent who loses a child to SIDS struggles with guilt, said Lorie Gehrke, a Walnut Creek mother who 10 years ago lost a daughter to SIDS and is now president of the SIDS Alliance of Northern California.

"I think all SIDS parents have guilt," Gehrke said. "Unfounded guilt, but guilt."

Leialoha is among those who struggled with a sense of guilt - her talk addressed how she coped with that, and rebuilt her shaken confidence in her ability to be a mother.

The cause of SIDS is still an enigma to researchers, but scientists at the conference spoke with optimism over new advances in understanding SIDS, as well as the 50 percent reduction in SIDS rates since the early 1990s.

Education is key

The sharp decline is credited to a public education campaign warning about the increased risk of SIDS in babies sleeping on their stomachs, as well as sharing a bed with an adult or an older child.

About 1 in 2,000 infants will die from SIDS in their first year, although the rate is slightly lower in California - roughly 1 in 2,500. California also passed a law in 1991 that authorized and supported research into SIDS, as well as expanding public-education campaigns.

The age of greatest vulnerability to SIDS is between birth and 6 months of age, when 90 percent of the deaths occur, according to Dr. Hannah Kinney, the event's keynote speaker and a professor of pathology at Harvard University.

This time frame coincides with the infant's transition from the fetus to life on the outside, when the child is exposed to new stimuli and dependent on its own system to maintain normal functioning.

Death occurs suddenly and without warning in SIDS when a baby is sleeping, or appears to be. It's also commonly known as "crib death."

African-American infants are two to three times more likely than white babies to die of SIDS, and Native American babies are three times as susceptible, according to the National Institutes of Health, as are indigenous populations in other parts of the world.

At the conference, researchers spoke excitedly of the work of Kinney and other researchers who are honing in on a biological basis for SIDS.

Kinney described abnormalities with the serotonin transport system in the brain stem that are strongly linked to SIDS. In that primitive region of the lower brain, serotonin plays a crucial role in governing breathing, cardiovascular function, arousal from sleep and other vital functions.

A gene linked to a deficiency in serotonin is found in blacks at more than twice the rate for whites, and blacks also have more than twice the rate of SIDS, noted Dr. Thomas Keens, professor of pediatrics at the University of Southern California.

A 2005 study by Kinney found that 50 percent of SIDS babies had abnormalities with this serotonin transport system.

This genetic trait, in combination with external factors like a baby disrupting its breathing by sleeping on its stomach or getting overheated, can lead to a failure of the infant's vital functions.

Another external risk factor, caused by a baby breathing into a pocket of air trapped in, say, a blanket or a pillow, could also trigger SIDS, researchers believe. This scenario is called "rebreathing."

When normal breathing is disrupted, the infant gets less oxygen, and carbon dioxide builds up in the blood, which inhibits arousal from sleep. Overheating, by placing too many blankets on a baby or sleeping next to parents or siblings, can also induce a deeper-than-normal sleep. If the baby isn't aroused from these perilous states, it doesn't have a chance to turn its head or in some other way correct the problem.

"When dangerous things happen while you're sleeping, the best thing you can do is wake up and deal with it," said Keens.

Researchers hope that as the serotonin system malfunction becomes increasingly validated as a cause of SIDS, it will enable the development of a SIDS screening test for newborns, as well as a potential treatment for babies and an accurate way to diagnose cause of death for sudden deaths in infants.

Still a mystery

Many cases of sudden infant death are labeled "unexplained," which compounds parents' grief, pointed out Gehrke, the Walnut Creek SIDS parent advocate, since there's an implication that perhaps the parent handled the baby in such as way to increase the risk of SIDS.

"Part of human nature is to find the reason and to lay the blame. When you're a new mom, you blame yourself," said Gehrke.

"And with that undetermined diagnosis, you end up believing it even more," she continued. "That's what's comforting about a SIDS diagnosis - that you didn't do anything wrong."

The death of Leialoha's son was labeled unexplained, which caused her and her husband, Mark, added anguish.

"You have to go through the grieving, you can't go around it," Leialoha said. "And I think it took us as long as it did because of the guilt I carried, that I was not to be trusted with a baby," she said.

"Now we're in a different place," Leialoha added, beaming as she patted her protruding stomach. The couple is expecting their second child in December.