What Causes SIDS?
What Causes SIDS?
Jessica and Ed Tamblin are boating enthusiasts who always look forward to the summer months. For years they have docked their cabin cruiser on a lake in Wisconsin, where they spend every weekend from late spring to early fall. After their twin boys were born, the four of them often stayed on the boat. They spent their days enjoying the sun and water, and at night they slept together at night in a large bed. Everything about their lives seemed to be going well, and they were very happy—until June 2000 when tragedy struck. The Tamblins woke up in the morning and found one of the twins, Justin, unusually still and silent. His skin was cold to the touch, and when they picked him up, he was unresponsive. They called 911 and tried to resuscitate him, but they could not. At the age of seven months, Justin was dead. His parents were devastated, feeling as though their happy life had suddenly been shattered.
Although years have passed since Justin's tragic death, Jessica Tamblin says that horrible day is permanently etched in her mind. She still cannot help crying whenever she talks about it. “It is impossible to describe the gut-wrenching pain Ed and I went through,” she says. “There are just no words. We wondered, how could this happen? Why did our baby die? Could we have done something to save him?”19When the cause of death was ruled to be SIDS, the Tamblins had mixed feelings, as Jessica explains:
In one way we were relieved to know it wasn't our fault, that there was no way we could have kept him from dying. But it really didn't do much to comfort us because the fact is, SIDS is a “nothing” diagnosis. It means nothing. Absolutely nothing. If they can't find anything that went wrong, they chalk it up to SIDS. For parents who desperately want answers, hearing something like that can leave you feeling pretty hollow inside.20
The Tamblins' grief over losing their baby was worsened by all the publicity that followed his death. Since the cause of the baby's death was not immediately known, newspaper articles speculated that Justin could have suffocated while sleeping in the same bed as his parents. “It was just not true,” says Jessica,
and it killed us to read that. The bed was huge and there was plenty of room for the babies and us. Neither of us rolled over on Justin—he was on the other side of the bed! And there weren't blankets on his face or anything like that. He just went to sleep and died. That's what happens with SIDS babies—they just die and no one knows why. Sometimes I wonder if newspaper writers even know how much damage their stupid assumptions do to people, and how cruel they are when they write things they know nothing about. It just hurts us so bad to think about it even now.21
Whether adults should sleep in the same bed with their babies is a controversial issue. Many health organizations, including the National Institute of Child Health and Human Development, urge parents never to sleep with infants. The Mayo Clinic says that adult beds are not safe for babies because they can become trapped and suffocate between headboard slats, the space between the mattress and bed frame, or between the mattress and the wall. The American Academy of Pediatrics (AAP) agrees, saying that bed sharing is more hazardous to babies than sleeping in their own cribs. A study published in the medical journal Pediatrics in November 2006 also linked bed sharing to several SIDS risk factors. The study focused on 239 babies from New Jersey who died of SIDS between 1996 and 2000. The researchers were from the SIDS Center of New Jersey at the University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School. In looking for patterns among bed-sharing babies who died of SIDS, the team found that 39 percent of them died while sharing a bed or couch. Those babies were more likely to have sleep risks such as sleeping with soft, loose bedding (pillows, quilts, or blankets) or to have slept in the same bed as other children.
Today, it is well known that SIDS and suffocation are two completely different causes of death. This was not the belief years ago, however. During the mid-1800s infants who died suddenly were assumed to have been smothered by their mothers. Brendon Curgenven presented a paper titled “The Waste of Infant Life,” which stated:
Suffocation at the mother's breast is the most common form; this frequently occurs on Saturday night; the mother, it may be, has been drinking, or goes to bed late; takes her child to her breast; falls asleep, and awakes in the morning to find her infant dead. In most cases the child's head slips off the mother's arm during sleep, its face becomes buried beneath the breast, the bed-clothes at the same time covering its head; it dies without a struggle suffocated by the carbonic acid exhaled from its own lungs. In winter these cases of suffocation occur most frequently in consequence of the mother unconsciously drawing the bed-clothes over her own shoulders.
Quoted in D.L. Russell-Jones, “Sudden Infant Death in History and Literature,” Archives of Disease in Childhood, 1985, p. 279.
Many people, including a number of physicians, do not believe that bed sharing puts babies at higher risk for dying of SIDS. Chiropractor Linda Folden Palmer, who authored the book Baby Matters, strongly disagrees with the AAP and other organizations that warn against bed sharing. She explains:
Reviewing study after study, the message is clear: The relative risk of death for infants sleeping in a safe adult bed with a safe parent is not greater than those found sleeping next to the parental bed, and their death risk is far smaller than those sleeping in a crib in another room. And, for infants over 2 or 3 months of age, the studies show a protective effect of co-sleeping over sleeping next to the parental bed.22
Palmer says that the AAP's recommendations against bed sharing are based on “sensationalized incomplete findings.”23 She cites one study that was done with 200 California infants who had died of SIDS. The researchers found that 45 of the infants died while co-sleeping: 35 were sharing their parents' bed, 6 were sharing a babysitter's bed, and 4 died while sleeping in their mothers' arms. Thus, co-sleeping was found to occur in only 22.5 percent of the SIDS deaths. At the end of the study, the authors reported “no significant relationship between routine bed sharing and the sudden infant death syndrome.”24
A major source of controversy over parents sleeping with infants is the theory that bed sharing reduces the risk of SIDS. According to professor of anthropology James J. McKenna, several studies have proven this to be true. One that was done in Saskatchewan, Canada, showed that SIDS cases were reduced among babies who co-slept with their mothers and were breast-fed. A study in South Africa showed that co-sleeping babies had higher survival rates than infants who slept alone. In Hong Kong, where co-sleeping is a normal family practice, SIDS rates are among the lowest in the world. This is also true in other Asian countries, as McKenna explains: “SIDS and infant mortality rates in general are decreasing to record low levels in Japan in parallel with increases in nighttime ‘bedsharing.’ In most other Asian cultures where cosleeping is also the norm (China, Vietnam, Cambodia and Thailand) SIDS is virtually unheard of.”25
Researchers throughout the world are studying SIDS in an effort to find the cause. One controversial theory is that SIDS is caused by toxic gases inside crib mattresses. In order to make mattresses flame retardant, chemicals such as phosphorus and arsenic are added during manufacturing. A fungus that commonly grows in bedding reportedly interacts with the chemicals to create poisonous gases. These heavier-than-air gases are concentrated in a thin layer on the baby's mattress or are diffused away and dissipated into the surrounding atmosphere. If a baby breathes or absorbs a lethal dose of the gases, the central nervous system shuts down, stopping breathing and then heart function. These gases can fatally poison a baby without waking him or her and without any struggle by the infant. A normal autopsy would not reveal any sign that the baby was poisoned.
De Montbrun is convinced that co-sleeping saved her baby boy's life. He was in bed with her the night that he suddenly stopped breathing. Because she instinctively knew that something was wrong, she woke up and was able to revive him. “I do not mean to imply that co-sleeping can prevent all SIDS deaths,” she writes:
It is a mysterious killer, and the answers are still to be found as to why so many babies are silently stolen from their parents… . What I do know is that I sensed something that night. A change in the little body that lay next to me. And that change woke me up. Would that have happened if he had been in a crib away or a room away from me? Could I have sensed a difference that far? I don't know the answer but I cannot bring myself to think of what [might have] happened if my son had not been in my bed that night … if I had chosen to follow the advice of countless people and parenting “experts” and had him in his own crib. It sends a chill down my spine.26
Although bed sharing is a widely debated issue, most scientists and health-care professionals agree on some risk factors for SIDS. One is that infants should always be placed on their backs to sleep. Studies have repeatedly shown that far more infants die from SIDS while sleeping on their stomachs. Betty McEntire, director of the American SIDS Institute, explains: “[M]ore convincing than any other fact is that belly-sleep has up to 12.9 times the risk of death as back-sleep.”27 Exactly why back sleeping reduces the risk of SIDS is not known, but scientists
do have theories about it. One is that stomach sleeping puts pressure on the infant's jawbone, which causes the airway in the back of the mouth to become narrower and hampers the ability to breathe. Another common theory is that stomach sleeping increases a baby's risk of rebreathing his or her own exhaled air. This is especially true when babies sleep on very soft surfaces or are surrounded by blankets, stuffed toys, or pillows. Exhaled air contains carbon dioxide, which is toxic when inhaled. When babies breathe it, the oxygen level in their bodies drops, and carbon dioxide accumulates in the lungs.
The concept of stomach sleeping versus back sleeping was originally born in Australia, New Zealand, and England. Health officials in those countries discovered that a much lower incidence of SIDS occurred when babies were placed on their backs to sleep. After hearing of these findings, the AAP endorsed the back sleeping concept. In 1992 the organization officially recommended that babies sleep on their backs for their first year of life. As a follow-up to the AAP's recommendation, in 1994 the National Institute of Child Health and Human Development launched a far-reaching publicity campaign known as Back to Sleep. At that time an estimated 70 percent of infants in the United States were sleeping on their stomachs. By 2002 the number was believed to have dropped to just over 11 percent. Many people credit the Back to Sleep program with the steady decline in SIDS deaths, as the AAP explains: “Since 1992, and consistent with a steady decrease in the [stomach] sleeping rate, there has been a consistent decrease in the SIDS rate.”28
Back sleeping cannot necessarily prevent SIDS, however. When Angi Suby put her baby Stephen Paul in bed for his nap, she placed him on his back. She made sure that he was not too warm or too bundled up. She also made sure that no stuffed toys or pillows were anywhere near him. Still, in spite of these precautions, SIDS claimed the baby's life. The same is true of many other babies. They still die of SIDS even though the parents do everything possible to reduce the risk, including placing them on their backs to sleep. That is one reason why some people reject the idea that a connection between SIDS and stomach sleeping exists. Increasing numbers of parents are placing their babies on their stomachs because they sleep more soundly that way. They believe that the benefits of sound sleeping outweigh the rare risk of SIDS. In an informal poll, which involved more than twenty-four thousand users of the Web site BabyCenter.com, nearly half of the respondents said that their babies slept on their stomachs. Those who advocate stomach sleeping say that doctors tell parents what they should do without living in the real world. Erica Lyon, who is a newborn-care instructor and the director of the RealBirth center in New York City, explains: “I'm very sympathetic to the mother who is so sleep-deprived that she puts the baby on its belly knowing that all the experts recommend not to. The role of the professional is to say ‘these are the recommendations and this is why.’ The role of the parent is to think critically and apply those recommendations in a way that makes their life manageable.”29
Even though people disagree over the role back sleeping plays in the development of SIDS, scientists say that smoking is a definite risk factor. Studies have shown that infants of mothers who smoked during pregnancy have a higher risk of dying of SIDS—as much as three times higher than babies whose mothers did not smoke. Exposure to secondhand smoke has also been linked to SIDS deaths. Health officials say that exposure to secondhand smoke doubles a baby's risk of SIDS death. According to William H. Gershen, an associate professor of pediatrics at the Medical College of Wisconsin, many SIDS deaths could be prevented if babies were not exposed to smoke either in the womb or after they have been born. He explains: “Believe it or not, probably the biggest risk factor for SIDS identified by current research is smoking, especially smoking by the mother… . Both smoking while the baby is in the womb and second-hand smoke after birth appear to be risk factors.”30 Studies suggest that smoking may affect the central nervous system of babies while they are still in the womb. If they continue to breathe secondhand smoke after they are born, they have a higher risk of developing SIDS than babies who are not exposed to smoke.
A study that was published in Sleep Review magazine in March 2008 reinforced the connection between smoking and SIDS risk. The study, which was conducted with laboratory rats, was based on the knowledge that when babies are in the womb, they receive oxygen from the mother. When they are born, they are exposed to lower oxygen, which signals their
glands to release chemicals that cause them to instinctively take their first breath and make their heart beat more efficiently. This protective mechanism remains in place for the first few months of the baby's life. After that, the central nervous system takes control and the mechanism is no longer needed. But according to the study, when babies are exposed to cigarette smoke (especially while they are still in the womb) the mechanism does not function long enough. Thus, the babies have a much higher risk of developing SIDS than infants who are not exposed to smoke.
Scientists generally agree about certain risk factors for SIDS, such as smoking. But another possible risk factor—childhood vaccinations—is much more controversial. Health officials from the CDC and other organizations say that no evidence of a causal relationship between SIDS and vaccines has been found. But many parents, as well as some doctors and researchers, are convinced that a link exists. This belief is based partly on the fact that numerous vaccines are routinely given before a baby is six months old, which is also the period of time when SIDS is most prevalent. According to the National Vaccine Information Center, a Food and Drug Administration database contains nearly five hundred reports of children who died of SIDS during the 1990s within three days of receiving the diphtheria, tetanus, and pertussis (DTP) vaccine. Of those reports, 58 percent listed SIDS as a “reaction” to the shot.
A 1985 study in Australia revealed startling findings regarding the connection between vaccinations and SIDS. Scientists Viera Scheibner and Leif Karlsson studied the breathing patterns of babies who had been immunized. They found that the infants' breathing was affected in a certain characteristic manner for forty to sixty-five days after they had received DTP vaccines. They also interviewed a number of parents who had lost babies to SIDS and learned that most of the babies had died after DTP injections. They concluded that an undeniable link between SIDS and vaccinations exists. Scheibner went on to study thousands of medical papers that dealt with vaccinations.
She was shocked to discover that no evidence existed in the papers about the effectiveness and safety of vaccines. “Cot (crib) death is caused by vaccines,” says Scheibner. “Vaccines are noxious substances. Serum of SIDS babies are so poisonous that all mice injected [with] minute amounts of it die.”31
Shelly Walker, who lives in Idaho, is convinced that vaccines can lead to SIDS. Walker's four-month-old son Vance was a happy, healthy baby whom she describes as “extremely full of life, energy and vitality.”32 In September 2007 Walker took him to a pediatrician's office for his vaccines. In one fifteen-minute visit, the baby was given a dose of Pediarix, which is a five-in-one shot for diphtheria, tetanus, pertussis, hepatitis B, and polio, as well as several other vaccines. Less than three days later Walker woke up at 5:15 A.M. and realized that the baby was unusually quiet. “I went to pick him up and then I screamed,”33 she says. Vance was still warm but he was not moving. Blood had crusted beneath his eyes, and bloody foam coming from his mouth was on his clothes and bedding. She frantically tried to resuscitate him while her husband called 911. But when the family arrived at the hospital, emergency room doctors told them that Vance was dead. They were consumed with shock and grief, as Walker explains: “I grabbed my baby in my arms and held him up and I screamed, ‘How … did this happen? Was it the vaccines?’”34 Vance's death was ruled to be SIDS, but Walker has no doubt that the vaccinations were responsible. She became even more certain when she learned about two other recent SIDS deaths. One baby died a week before Vance, and the other died a month later—after both of them had received the same vaccines at the same pediatrician's office.
Whether vaccinations contribute to the development of SIDS is not known with any certainty. But because such a link is possible, scientists continue to investigate the connection. They are also pursuing many other studies in an effort to find what causes SIDS. Although much progress has been made, scientists are the first to admit that all they have are theories. Smoking is thought to be a high risk factor, and many health-care professionals believe that stomach sleeping is as well. Issues such as co-sleeping and vaccinations are highly controversial, with strong viewpoints on both sides. Because SIDS continues to kill several thousand babies each year, and because there is no proven way that it can be prevented, researchers and health-care officials feel a sense of urgency to find what causes it. According to Kattwinkel, SIDS is as mysterious today as it always has been. “If we knew exactly what causes it,” he says, “we wouldn't call it SIDS.”35