What Do We Know About SIDS?

Cases of what we now know as SIDS have been recorded since Biblical times, but it was not until 1969 that most doctors and other health professionals agreed about what SIDS is. The current definition, used since 1989, is "the sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and a review of the clinical history." This definition highlights the importance of the death scene investigation. Although much has been learned about SIDS in the past 30 years, scientists still cannot point to one definite cause or causes, and unfortunately, there is no way to prevent SIDS from occurring. But there are some basic facts that are known..

We Know That SIDS Is:

l the major cause of death in babies from 1 month to 1 year of age - and most SIDS deaths occur when a baby is between 2 and 4 months old l sudden and silent - in most cases, the baby seemed healthy l unpredictable and unpreventable l a death that occurs quickly, usually while the baby is asleep l a death that causes no suffering for the baby l determined only after a complete autopsy, an examination of the death scene, and a review by a doctor or other health professional of the baby's case history l a diagnosis of exclusion - all other causes of death are ruled out l recognized by doctors and other health professionals as a medical disorder, listed in the International Classification of Diseases, 9th Revision (ICD-9)

We Know That SIDS Is Not:

l caused by vomiting, choking, or some minor illness such as a cold or infection l caused by the diphtheria, pertussis, tetanus (DPT) vaccine or other immunizations l contagious l child abuse l the cause of every sudden or unexpected infant death.

How Do We Know It Was SIDS?

SIDS is called a diagnosis of exclusion - the only way the doctor can be certain the baby died from SIDS is to make sure that there was nothing else that could have possibly caused the baby's death. That is why an autopsy is so important - so that the doctor or medical examiner can conduct a thorough postmortem investigation that is focused on finding any physical condition or environmental factor that could have led to the death. Only when every other possible cause is ruled out, should the doctor or medical examiner make a diagnosis of SIDS.

Why Is It So Difficult To Find A Cause Of SIDS?

Finding a cause for any disease is a long and difficult trial-and-error process. This is especially true of SIDS, where the baby seemed healthy and there are no visible warning signs. Since 1963, Government and private researchers have been probing, studying, and, sometimes, discarding theories about what causes SIDS and continuing to search for ways to prevent such deaths. These scientists study family background as well as the prenatal and birth history; diet; record of allergies, immunizations, or illnesses; behavior and personality; sleeping habits and positions; and the effects of environment on infant health. In their study of SIDS victims and normal infants, scientists are trying to identify differences in the heart and lung, nervous, and immune functions of healthy babies and compare those same functions in SIDS babies to determine what, if anything, makes SIDS babies different. By analyzing information from normal, premature, or ill infants and comparing it to information about babies who died of SIDS, researchers are attempting to detect the statistical patterns and trends (called epidemiology) of SIDS. In addition to reviewing information from postmortem examinations, scientists are also studying conditions such as infant apnea (temporary stoppage of breathing) and apparent life-threatening event (ALTE) and their relationship (if any) to SIDS. ALTE is characterized by a combination of apnea, change in skin color, obvious change in muscle tone (usually limpness), or choking or gagging. In the past, ALTE was sometimes referred to as "near-miss SIDS" or "aborted crib death." These terms are no longer used because scientists still differ in their opinions about the relationship of ALTE to SIDS. Researchers also engage in extensive biomedical research (studies of human infants and of animals whose early development is similar to that of humans). Some of this research is focused on what is termed fetal predisposition - some condition (or conditions) that makes the fetus unable to overcome the normal internal and external stresses that occur in the intrauterine development of every baby. Other scientists continue to study babies' sleep patterns, how infants awaken themselves, how they continue breathing while they sleep, and other aspects of sleep that may help them understand the relationship of sleeping and SIDS. A great deal of current SIDS research is centered on the nervous system of SIDS infants. Some scientists think that SIDS babies may have defects in the parts of the nervous system that control breathing and heart rate. Other researchers are trying to identify disorders in infants' metabolism and determine how those disorders react to changes in an infant's body or surroundings to result in sudden death. Still other scientists are studying certain chemicals in the brain that affect the functioning of the heart, lungs, and other vital organs. In addition to pursuing and expanding these research efforts, scientists are also examining other aspects of SIDS such as learning and behavior in infants and the usefulness of home monitoring equipment. Since the late 1980's, pediatricians, physiologists, and other researchers have been reexamining the relationship of sleep position to SIDS. In the United States, the most common sleep position for infants has been on the stomach (prone). recent studies from abroad have implicated the prone sleeping position with a greater risk of SIDS. With this evidence in hand, the American Academy of Pediatrics (AAP) issued a statement on April 15, 1992, recommending that "normal infants, when being put down for sleep, be positioned on their side or back" (Pediatrics, 1992). The National Institute of Child Health and Human Development (NICHD) intends to monitor the AAP's recommendations and their impact on changes in practice with regard to infant sleep position. The NICHD is supporting critical research to investigate why the prone sleeping position may make an infant more vulnerable to SIDS.

Why Do An Autopsy?

Health professionals consider an autopsy necessary because a definitive SIDS diagnosis cannot really be made without a thorough postmortem examination and investigation that fails to point to any other possible cause of death (hence the term, "diagnosis of exclusion"). Furthermore, if the cause of SIDS is ever to be uncovered, scientists will most likely detect that cause from evidence gathered by studying tissue samples or written autopsy reports. In this painstaking and complex process, researchers are trying to isolate specific characteristics or conditions (called "markers") that occur in SIDS victims and that do not occur in non-SIDS infants. By finding these markers, scientists hope to identify those babies most likely to die from SIDS and develop ways to prevent those deaths. Although researchers still do not know what causes SIDS, their efforts have led to the elimination of certain early theories that were misleading or incorrect for example, we now are sure that SIDS is not caused by choking or by neglect. We know that SIDS is not contagious. Most researchers now believe that babies who die of SIDS are born with one or more conditions that make them unable to deal with normal stresses that occur as infants develop. Scientists have identified some typical characteristics that indicate that SIDS is a distinct medical occurrence. For example, when examining tissue samples from SIDS autopsies, scientists have observed several microscopic changes. Researchers have noted the increased number of star-shaped cells in the brainstem. They have also reported that very tiny red or purple spots on the surface of the heart, in the lungs, and thymus occur in almost 80 percent of all SIDS cases. It is only by continuing to study and identify these and any new differences between SIDS babies and babies who died from other causes that scientists can uncover the cause or causes of SIDS.

Do We Know What SIDS Babies Have In Common?

Experts still cannot predict which babies will die from SIDS, but recent research has helped to identify those infants who may have an increased chance (or risk) of dying from SIDS. SIDS occurs in all types of families, among all races and income levels. SIDS is unexpected, occurring in an otherwise healthy baby, usually when the baby is 1 month to 1 year old and the greatest number of SIDS deaths take place between 2 and 4 months after birth. A SIDS death is sudden, and the baby shows no signs of suffering. SIDS is usually associated with periods of sleep. More SIDS deaths are reported in the fall and winter. Somewhat more male than female babies die from SIDS. Scientists have also found certain characteristics that seem to occur more often among SIDS babies. Blue discoloration of the skin because of an insufficient supply of oxygen to the blood (called cyanosis), accelerated heartbeat (called tachycardia), breathing problems or accelerated breathing (called tachypnea), poor feeding, irritability, or low body temperature (called hypothermia) are risk factors that have been identified in more SIDS newborns than non-SIDS newborns.

What Do We Mean When We Say A Baby Is 'At-Risk' For SIDS?

When we talk about risk factors, we are referring to those environmental and behavioral influences or conditions that can provoke ill health. Scientists study one specific characteristic (or group of characteristics) such as sex, age, or race and try to determine how much more common that condition (or risk factor) is in a group of people (or population) suffering from a particular disease or physical ailment compared with a population that is not suffering from that disease or ailment. Risk factors are supposed to increase a person's chance of being born with or developing a disease or condition, but there is no way to say that someone will definitely be born with or acquire the condition or disease just because he or she is known to have those risk factors. Any risk factor may be a clue to finding the cause of a disease, but risk factors are not causes. For example, because almost 80 percent of SIDS deaths occur by the age of 6 months, infants in this age group can be considered to be at increased risk. It is obvious, though, that age is not a cause of SIDS. Scientists are quick to point out that most risk factors are elements over which most of us have no control - factors such as our sex, race, birth weight, or birth order; or the age of our mothers when we were born; or our parents' occupations, incomes, or education levels. There are some risk factors, though, that can be controlled. Researchers know that the mother's health and behavior during her pregnancy and the baby's health before birth seem to somehow influence the occurrence of SIDS. Even this information, however, is not reliable in predicting how, when, why, or if SIDS will occur. For example, we know that smoking during pregnancy, maternal age less than 20, poor prenatal care, low weight gain, anemia, use of illegal drugs, and history of sexually transmitted disease or urinary tract infection are associated with a harmful prenatal environment. However, scientists are not prepared to state that smoking causes SIDS, and we know that not every mother younger than age 20 will have a SIDS baby. Furthermore, SIDS occurs in babies whose mothers have never smoked or who are older than age 20. But what scientific studies tell us is that the chance for SIDS to occur is somehow increased if a mother smokes while pregnant or if she is younger than age 20, or has other risk factors. Although the relationship between these risk factors and SIDS is not yet clear, it is obvious that by refraining from smoking, by eating properly, and by obtaining adequate prenatal care, a mother can increase the chance for a healthy and normal infant. Some recent studies indicate that certain conditions do not seem to increase the risk for SIDS. Based on reports from parents, SIDS infants do not seem to have more colds or fevers than non-SIDS infants. Information gathered from medical records and interviews from parents strongly suggest that there is no association between DPT vaccinations and SIDS. Newborn apnea (temporary stoppage of breathing) does not appear to increase the chance for SIDS. Apnea through the first year of life, however, does continue to be a focus for intense scientific investigation.

How Many Babies Die From SIDS?

Based on information recorded on death certificates, collected by State offices of vital statistics, and sent to the Federal Government, the number of SIDS deaths tends to remain the same, despite changes in the number of infant deaths from all other causes. According to the National Center for Health Statistics, there were 5,476 SIDS deaths in 1988, 5,634 deaths in 1989m, 5,417 in 1990, and 5,349 in 1991. Other sources estimate that the number of SIDS deaths in this country each year may be considerably greater. This larger estimate accounts for cases that should have been recorded as SIDS but were not, possibly because complete or thorough postmortem examinations had not been conducted. SIDS accounts for 14 percent of all infant deaths reported each year and SIDS remains the leading cause of death in the United States among infants between 1 month and 1 year of age. Furthermore, SIDS is second only to birth defects as the leading cause of death among all infants less than 1 year of age.

Coming To Terms With Your Grief .

Babies are not supposed to die. The first few months after a baby's birth are times of happiness; there is that wonderful feeling of the growing physical and emotional attachment between the baby and the parents. Suddenly, an apparently healthy infant is dead. In most cases, the death occurred after the baby was put down for sleep, usually at home - a time and place that is associated with warmth and security. The baby's life has ended before it really began, and all parental expectations and hopes have ended abruptly. There is no time to prepare, and there is no adequate explanation for the death. The involvement of the legal and medical systems often means a loss of privacy at a time when members of the family want to be alone with their grief. There may be possible community suspicion and rejection. Very often the loss of an infant is a couple's first encounter with death and personal loss. Bewilderment and numbness characterize most parents' reactions to their child's death. Because the baby's death cannot be explained by an obvious cause, many couples blame each other or themselves. Parents may feel that somehow they have failed - that there was something that could have been done to prevent the death. These feelings of guilt are common. But parents must understand that there was nothing that could have been done. After the initial shock begins to wear off, parents may find it difficult to get to sleep or stay asleep, even when tired and may feel "down" all the time. Parents may find it difficult to concentrate on any task or activity for any length of time. They may experience other physical ailments or symptoms. Regular eating habits may change - from having no appetite to eating to excess. Parents often feel like just "wanting to escape." It is normal for mothers and fathers to express their grief in different ways. Women tend to cry and "talk out" their grief, whereas most men tend to grieve in silence. Parents working outside the home may become overly engrossed in their work, while those staying at home may seek comfort from constant reminders of the baby. All of these feelings are normal reactions to grief. but, if any of these feelings or behavior persist, seeking professional counseling from the family doctor, nurse, or clergy may be necessary.

The Effect Of A SIDS Death On Other Children

If there are other children, parents may find themselves fearing for their safety, so much so that they have a hard time letting them out of their sight. At other times, parents may become suddenly impatient with the child for no real reason or find it almost impossible to carry on the daily responsibilities of family life. It is important to understand that the surviving children are also trying to deal with the death of their brother or sister. They are frightened and confused, and they unconsciously sense that their lives will be changed forever by the baby's death. Children may feel that they will now be expected to live for two, or they may construct a protective wall of silence around themselves. They may be confused about whether or not it is all right to talk about their dead baby brother or sister - or even acknowledge that the baby ever existed. Surviving children may feel especially guilty for resenting all the attention lavished on the new baby. Did they somehow wish the baby's death? They may be particularly troubled in the case of a SIDS death because the baby seemed healthy and normal, just like themselves. They may be fearful because the baby died while asleep or at rest. Could it happen to them? Surviving children need to feel that they can talk about these thoughts or ask questions. Young children may have some very frightening thoughts that they cannot express. They may need special attention from parents and other family members or from the family doctor, nurse, or other professional. Older children should be told as much as they are able to understand. It is extremely important that a parent acknowledge the disruption to the family unit caused by a SIDS death. Parents need to convey to the surviving children that what they are all feeling is natural and part of the grieving process.

Relatives and Other Caregivers

Sometimes relative or baby-sitter may have been caring for the infant when the death occurred. It is not uncommon for partners to blame the relative or baby-sitter. Parents may blame themselves for having left the baby with someone else. It is natural that they may not be able to understand that the caregiver is also experiencing sorrow and guilt. This is a particularly painful situation; and counseling may be helpful for all involved.

The Community's Reaction To A SIDS Death

It is important that SIDS parents understand that some members of the community may have little or no information about SIDS, or they may not understand that it is an accepted and appropriate designation as an official cause of death. Parents should be aware that some members of the community may blame them for the death and may view police or medical involvement in a SIDS case as a clear sign that the death occurred under suspicious circumstances. Unfortunately, in some communities, even today, SIDS parents are wrongly suspected of causing the death of their baby. It is also true that many people in the community may be extremely sympathetic and want to express their support and concern for the parents and family. They may, however, be unsure or uncomfortable about how to go about expressing their support. The bereaved parent needs to deal with each person and situation on an individual basis, depending on that person's relationship to the family.

Seeking Support

SIDS parents may find themselves suddenly dealing with counselors, members of the clergy, medical and public health professionals, law enforcement personnel, and emergency responders as well as neighbors and other in the community. The support of many people is important during the bereavement period. But, at times, a parent may feel somewhat overwhelmed and resentful that these people are involved in his or her private life and the life of the family. At especially difficult times, it may be helpful to talk with a member of a peer support group. The group members are there to help a newly bereaved parent begin to cope with the loss and provide support during this period of grief. The support group gives a parent the opportunity to meet other parents who have also lost a baby to SIDS and who want to extend their friendship and understanding. New SIDS parents may find it easier to talk about the baby and express feelings of grief within a group of people with similar experiences. The suddenness and unexpectedness of a SIDS death makes it especially difficult, leaving parents with a great sense of loss, a need for understanding, and a need to know what has happened. Family members and professionals directly involved with SIDS parents, and even others in the community, are often left with a deep sadness and feeling that something should have been able to prevent the death. But, at this time, SIDS cannot be prevented and researchers are still unclear about its causes. Right now, the strongest weapon we have is to educate and inform ourselves, families, and friends concerning the real facts about SIDS. If you know anyone who has lost a baby to SIDS or who wants more information about SIDS, please pass this brochure on to them or suggest that they call or write to the following organizations.

Where To Get More Information About SIDS

Massachusetts Center for Sudden Infant Death Syndrome Boston Medical Center 818 Harrison Avenue Boston, MA 02118 (617)534-7437 (800)641-7437

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