For centuries, parents have struggled to comprehend a tragic phenomenon in which seemingly healthy infants are found dead in their cribs.
But Pomona College anthropologist James J. McKenna has sparked national interest with an unusual theory for reducing the incidence of Sudden Infant Death Syndrome.
After sleep studies with mothers and babies at UC Irvine, where he holds a part-time appointment in psychiatry and neurology, McKenna said he believes that infants who sleep with their mothers receive sensory cues that infants who sleep alone never get.
And, he suggested, these "infant arousal" cues--rocking, skin-to-skin contact, warmth, the rhythm of the mother's breathing--may lower a baby's risk of dying of SIDS.
"I do not suggest . . . that all parents should sleep with their infants," he wrote in a recent issue of the journal Human Nature.
Still, McKenna said he does believe that "parent-infant sleep contact" can overcome the "natural physiological vulnerabilities of the neurologically immature human infant." That physical contact, he said, may prompt an infant whose immature respiratory system has failed to start breathing again.
Although much of what he says about the virtues of infants and parents "co-sleeping" is still theory, earlier this month McKenna and his collaborator, sleep expert Sarah Mosko, received approval for a three-year, $700,000 grant from the National Institute of Child Health and Human Development to study physiological responses between mothers and infants.
However, because a national committee has asked for revisions, the study may not be funded this year, federal official Marian Willinger said. However, Willinger added, "It's a novel idea that has not really been pursued before."
For years, nearly all SIDS research has focused on defects in the baby, such as problems in cardiac function, infant respiration or neural mechanisms controlling sleep. Still, the phenomenon that kills 7,000 American babies a year--30 to 50 in Orange County--remains largely a mystery.
But McKenna's theory, focusing on the social environment of mother and child, is "an intriguing hypothesis" that merits additional study, Willinger said.
It is also controversial. Dr. Alfred Steinschneider, president of the American Sudden Infant Death Syndrome Institute in Atlanta, complained that the theory lacked supporting data and that to believe in it takes "just leaps of faith."
He also noted: "In your great-great-grandparents' time . . . parents used to sleep with babies all the time. And you know what? Babies died of SIDS."
Steinschneider and other experts on the malady note that the Old Testament's "Book of Kings" contains the first documented case of SIDS: "And this woman's child died in the night; because she overlaid it."
For centuries, SIDS experts said, babies in their first year of life have died suddenly, and their mothers have been blamed--often unfairly--for rolling onto and suffocating their infants.
Longtime SIDS researcher Marie Valdes-Dapena, a pediatrics and pathology professor with the University of Miami, was intrigued by McKenna's thesis.
"It's probably very natural and very wholesome for a baby to sleep with mother," she said. "Now, whether there is some kind of reciprocal reaction on the part of the baby in response to the mother . . . it's a very provocative thought."
McKenna, 41, came to a possible explanation for SIDS through an unusual route--partly from anthropology background and partly from personal experiences with his infant son.
As an anthropologist, he knew that cultures around the world--in Indonesia, Sweden, Japan--considered it normal to sleep with a baby. And when their son, Jeffrey, was born in 1978, McKenna and his wife, Joanne Mack, decided to share the responsibilities of parenting as well as sleep with their baby.
While caring for Jeffrey during the day, McKenna said he would lie quietly beside his son when he took his afternoon nap. And gradually, McKenna said, he noticed "the baby seemed sensitive and responsive to my breathing. I noticed if I sighed and breathed rhythmically, he breathed rhythmically as well. And I used to play little games--changing my breathing--and he would open his eyes.
"Also, not only was he responsive to me, I was responding to him," McKenna said. "His pattern of breathing affected me and we would both fall asleep together."
Calling on that experience four years later at an international psychiatry conference in Cannes, McKenna suggested that a parents' presence could affect a sleeping infant and that perhaps "the nocturnal separations" of American parents from their babies could be a factor in SIDS. The response to those remarks was so enthusiastic, McKenna said, that he decided to explore it further.
In a series of recent papers in Human Nature, McKenna has noted that SIDS rates tend to be lower in cultures where co-sleeping is common. Although the SIDS rate in the United States is 2 per 1,000 live births, it is only .06 in Sweden, .31 in Israel and .15 in Japan, where co-sleeping is the norm, he said.
In a related article, McKenna described some of his research with monkeys, noting that infant monkeys showed stress, despair, a decreasing heart rate and lowered levels of antibodies when separated from their mothers.
And in an article published this month, McKenna and collaborator Mosko--a psychologist who now directs the sleep lab at St. Joseph Hospital in Orange--described results of their sleep studies in 1987 and 1988.
They monitored five mothers and their healthy, 2- to 5-month-old babies, hooking each mother-baby pair up to sensors that recorded breathing, heart rates and brain activity as they slept overnight in a single bed.
They reported finding an unusual degree of "synchrony" in each pair's breathing and sleep-wake cycles throughout the night. When the baby awoke briefly or stopped breathing a few seconds, often the mothers did too, the studies showed.
Told of the results, one mother from the study was not surprised. Marylin Ferrey, 29, of Mission Viejo, said that when she slept with her son Antoney, then 3 months old, "his breathing would become like mine." But she added, "I've always slept with my kids part of the night" and more when they were sick because "if they have a fever, or trouble breathing, I'll know."
McKenna quickly concedes that the UCI sleep study does not prove that mothers who sleep with their babies can prevent SIDS.
"It's not like I'm saying, 'Sleep with your baby and prevent SIDS,' " he said. There's "a big gap" between that conclusion and his research so far. For now, he said, "I don't have any proof."
Still, McKenna said he hopes the three-year, federally funded study will add to their understanding of SIDS by studying sleep reactions of 25 mother-infant pairs, including perhaps some infants considered at high risk for SIDS.
Said Mosko, "We just have a little tiny kernel of data. . . . Do we have the answer to SIDS? No. But does anybody else have the answer to SIDS? No."
For all that, McKenna admits a bias toward co-sleeping. "I feel Americans should know that it is perfectly normal and natural for parents to sleep with the baby," he said.
"We now have the Fisher-Price walkie-talkies to bring the sound of your baby into the parents' room. That isn't what is needed," the anthropologist said.
Rather, he said, the baby "needs to hear Daddy snoring or wheezing, or to feel mother's stroke, Daddy's stroke. This whole notion of putting a baby in a sensory-deprived bedroom is completely alien to everything we know about evolution."
FACTS ABOUT SIDS
Sudden infant death syndrome (SIDS), the major cause of death for infants from 2 weeks to 1 year of age, claims the lives of one of every 500 American babies--almost one baby every hour.
* Although SIDS strikes infants of all races and socioeconomic levels, certain groups of infants are considered at slightly higher risk: infants 2 to 4 months of age; low-birth weight infants as well as premature babies, twins and triplets; infants born to teen-age mothers and to mothers who smoke. Boys are at slightly higher risk than girls.
* The largest number of SIDS deaths occur in winter.
* Most deaths occur during the night or nap time and after a minor illness, such as a cold.
* Death occurs within seconds, usually during sleep. The baby does not suffer.
* No association has been found between administration of childhood vaccines and SIDS.
* SIDS is not caused by suffocation or aspiration, though sometimes death certificates use such terms in error.
* Researchers believe babies die of SIDS for a number of reasons, not just one. They also believe that some subtle abnormality, which may be traced back to fetal development, predisposes some babies to SIDS.
* Since the cause of a SIDS death is unknown, there is no specific means of preventing it.
* More information about SIDS, as well as support for grieving families, is available by calling the SIDS Alliance, (800) 221-SIDS. The Sudden Infant Death Syndrome Alliance, Columbia, Md., a nonprofit national organization, provides emotional support for families that have lost a child to SIDS, clinical services to infants at risk, and helps fund medical research into SIDS.