Sudden infant death syndrome (SIDS) is the death of a baby younger than one year of age that occurs suddenly and unexpectedly, and which cannot be explained after the postmortem study, which includes a complete autopsy, the investigation of the place of death, and review of the child’s medical history.
Sudden infant death has no symptoms, its causes are unknown, and it occurs unexpectedly, but some measures, such as putting the child to bed on their back, have decreased their incidence.
The autopsy is essential to verify that the causes of death are natural and to exclude trauma due to ill-treatment. However, it is not enough to distinguish sudden death from intentional suffocation, so it is necessary to resort to the assessment of the place of death and the complete medical history of the child.
In western countries, sudden infant death syndrome is the most common cause of death in babies between one and twelve months of age, especially between two and four months, and it affects more boys than girls .
There are no characteristic findings, nor is any specific finding required at autopsy to diagnose this syndrome, which is established by exclusion, when no reason is found to justify the baby’s death.
However, some frequent features can be observed. In more than 90% of cases, hemorrhages are found that can be more extensive than in neonatal deaths from other causes. Pulmonary edema (puddling of the lungs) may also be seen. Data are usually found indicating previous low-intensity chronic suffocation in most cases, as well as the persistence of brown fat (found in children and disappearing as they grow), or liver erythropoiesis (production of cells blood from the liver, typical of the intrauterine stage) among other structural alterations.
Some studies indicate that a small group of patients with sudden death syndrome have low development of the arcuate nucleus, a region of the brain responsible for cardiorespiratory control, and which is also involved in the control of awakening and other functions.
Overall, deceased infants show delayed prenatal and postnatal growth, and molecules have been found that indicate a relatively long period of oxygen starvation in tissues prior to death.
Low levels of certain neurotransmitters in the brain, involved in cerebral respiratory control, have also been described, so that their deficit causes disorders in the cardiorespiratory control of affected children.
Some postmortem molecular analyzes have identified genetic mutations associated with cardiac disorders, so some deaths could be related to a fatal arrhythmia.
Despite the numerous studies and autopsies carried out on babies who died suddenly and inexplicably, the cause of this syndrome is currently unknown, although specialists estimate that more than a single factor, these deaths are due to a set of various factors.
The relationship between sleeping prone posture (upside down) and the risk of sudden death has been consistently demonstrated. By decreasing the frequency of this posture among the general population, the risk has increased among infants who still use it for sleep. The greatest risk occurs in infants who do not usually sleep prone, but who were placed in this position in the last dream, or who were found to have adopted this position when found.
Although sleeping on your side is much safer than sleeping on your stomach, children who sleep in this position have twice the risk of dying as those who sleep on their back, since children placed on their sides can roll and end up on their stomach. Therefore, the current recommendations are to place all infants in a supine position to sleep (on their back), unless the pediatrician contraindicates it.
Environment in which the infant sleeps
Soft surfaces such as comforters, pillows, sheepskin, and old or soft mattresses also increase the risk of sudden death. Head and face may be covered by poorly fitted bedding, such as heavy duvets, which also increases the risk; as does overheating, especially elevated room temperature, increased body temperature, sweating, or excess clothing or bedding.
Breastfeeding has not been shown to protect against sudden death, but this form of feeding is recommended because it boosts the baby’s immune system and protects it against infection, although upper respiratory infections have not been shown to be a factor in risk.
Pacifier use is associated with a slightly lower risk of sudden death, so it could be considered protective. Immunizations are also not a risk factor.
Causes of syndrome sudden death
The cause of SIDS is unknown. Today, many doctors and researchers believe that SIDS is caused by many factors, including:
- Problems with the baby’s ability to wake up (sleep stimulation)
- Inability of the baby’s body to detect accumulation of carbon dioxide in the blood
- Rates of Sudden Infant Death Syndrome (SIDS) have dropped significantly since doctors began recommending that babies lie on their side or back to reduce the likelihood of the problem. However, SIDS is still a major cause of death for babies younger than 1 year old. Thousands of babies die from this cause annually in the United States.
SIDS is more likely to occur between 2 and 4 months of age and affects boys more than girls. Most SIDS deaths occur in the winter.
The following factors may increase the risk of SIDS:
- Sleeping on your stomach
- Being in an environment with cigarette smoke while in the womb or after birth
- Sleep in the same bed with their parents (sleep together)
- Soft bedding in cribs
- Multiple births (being twins, triplets, etc.)
- Premature deliveries
- Having a brother or sister who suffered from SIDS
- Mothers who smoke or consume psychoactive substances
- Being born to a teenage mother
- Short time intervals between pregnancies
- Late prenatal care or lack of it
- Living in poverty
Although studies show that babies with the aforementioned risk factors are more likely to be affected, the impact or importance of each factor is still not well defined or understood.
Why is sleeping on your stomach dangerous?
SIDS is more likely among babies who lie on their stomachs than among those who lie on their backs. A baby should also not be put to sleep on its side. The baby could roll over easily during sleep and go from lying on its side to lying on its stomach.
Some researchers believe that sleeping on your stomach could cause a blockage of the airways and make breathing difficult. When sleeping on the tummy, the baby is more likely to breathe the air he has just exhaled, especially if he is sleeping on a soft mattress or with padding, stuffed animals or a pillow near his face. As the baby breathes in the air he breathes out again, the body’s oxygen level drops and the carbon dioxide level rises.
Babies who die from SIDS may have a problem in the part of the brain that helps control breathing and sleep disruption. If a baby is breathing stale air and is not getting enough oxygen, the brain often sends a signal for the baby to wake up and cry to get more oxygen. If the brain does not emit this signal, oxygen levels will continue to drop.
What is “Sleeping on your back”?
In response to evidence that sleeping on the stomach can promote SIDS, the American Academy of Pediatrics (AAP) created the “Sleeping on the Back” campaign, which recommended putting all healthy babies under one year of age to sleep on their backs. .
Babies should be put to sleep on their backs until 12 months of age. Older babies may not lie on their backs all night, but that’s not a problem. Once the baby learns to roll over, from lying on his back to his stomach and vice versa, he can remain in the sleep position of his choice. No need to use positioners or devices that claim to reduce the risk of SIDS.
Some parents worry about “flat head syndrome” (postural plagiocephaly). In plagiocephaly, babies develop a flat area on the back of the head because they spend too much time lying on their back. Since the “Sleeping on the Back” campaign began, this problem has been more frequent, but can be easily treated by changing the baby’s position in the crib and allowing him to spend more supervised tummy time while awake.
Many parents fear that if they put their baby to sleep on his back, he could choke on a spit or vomit. However, only babies with some rare upper airway malformations may need to sleep on their tummy. There is no increased risk of drowning in healthy babies and most babies with gastroesophageal reflux (GER) who sleep on their backs.
Parents should speak to their child’s doctor if they have questions about the best position for their baby to sleep.
What is “Safe when sleeping”?
After the AAP’s recommendation, the SMSL rate was greatly reduced. Still, SIDS continues to be the leading cause of death in young babies. The “Safe Sleeping” campaign is a continuation of “Sleeping on the Back” and reminds parents and caregivers to put babies to sleep on their backs and provide them with a safe environment to sleep.
Here’s how parents can reduce the risk of SIDS and other sleep-related deaths:
- Place your baby to sleep on a firm mattress, never on a pillow, water bed, sheepskin, an armchair, a chair, or other soft surface.
- Cover the mattress with a tight-fitting sheet and no other white clothing. Keep soft objects and loose white clothing away from where the baby sleeps.
- Do not use padded protectors in cribs. Padded protectors can suffocate or strangle the baby.
- Share the room without sharing the bed. Experts recommend that babies sleep in the same room as their parents (but on a separate surface, such as a bassinet or crib by the parents’ bed) until one year of age or for at least 6 months, when the risk SMSL is higher.
- Breastfeed, if possible. The greatest protection is obtained by feeding the baby exclusively breast milk, but any amount of breast milk has been shown to reduce the risk of SIDS.
- Put your baby to sleep wearing the pacifier for the first year of life. If your child refuses the pacifier, don’t force him to sleep with him. If you drop the pacifier while you are asleep, you do not need to put it back on. If you breastfeed, offer a pacifier only when breastfeeding is firmly established.
- Make sure your baby is not too warm when sleeping. Dress your baby according to the temperature of the room, without sheltering him more than necessary. Watch for signs of overheating, such as sweating or being very hot to the touch.
- Do not smoke during pregnancy or after birth. Babies of women who smoked during pregnancy are more at risk for SIDS than those whose moms never smoked; Exposure to secondhand smoke also increases the baby’s risk, and that risk is very high if one parent is a smoker and shares the bed with the baby.
- Do not use alcohol or drugs during pregnancy or after birth. Parents who drink or use drugs should not share a bed with their baby.
- Make sure your baby receives all the recommended vaccinations. Studies show that babies who get vaccinated have a 50% lower risk of SIDS.