Researchers may have found a cause of Sudden Infant Death Syndrome

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Sudden Infant Death Syndrome (SIDS) is the leading cause of death in babies in the first year of life. It is responsible for about 2,000 infant deaths in the United States according to the CDC.

Now, there may be hope for solving the mystery over why the deaths occur.

Researchers at Boston Children’s Hospital have found many babies that die “suddenly and unexpectedly” have “underlying brainstem abnormalities and are not all normal prior to death.”

The hospital published its findings in the December issue of Pediatrics.

“These abnormalities impair brainstem circuits that help control breathing, heart rate, blood pressure and temperature control during sleep,” the hospital wrote in a press release on the finding of  neuropathologist Dr. Hannah Kinney and her team. “The researchers believe [the abnormalities] prevent sleeping babies from rousing when they rebreathe too much carbon dioxide (due to inadequate ventilation), breathe too little oxygen or become overheated (from overbundling).”

Here is an excerpt from the hospital’s press release:

In the new study, Kinney and colleagues asked if all these infants are truly normal. They reexamined their data, reviewing the cases of 71 infants who died suddenly and unexpectedly, were autopsied at the San Diego County Medical Examiner’s office from 1997 to 2008, and had brainstem samples available for analysis. The researchers grouped the infants according to sleep circumstances—those that were considered likely to generate asphyxia and those that were not—based upon death-scene investigation reports.

In the end, they compared 15 infants with SIDS whose deaths were deemed not to involve asphyxia (group A), 35 SIDS infants whose deaths were possibly asphyxia-related (group B) and 9 infants who clearly died from other causes (controls). They excluded the other infants, who either had insufficient data or had evidence of other clear risk factors for death, such as exposure to drugs or extremes of temperature.

Brainstem neurochemical abnormalities—involving serotonin, serotonin receptors, GABA receptors and 14-3-3 (a protein that regulates serotonin)—were found in both group A and group B. Infants in these two groups—with and without environmental risk factors for asphyxia—had the same brainstem abnormalities, and both groups differed significantly from the controls.

“Even the infants dying in a potentially asphyxia-generating situation [sleeping face down or next to an adult] had an underlying brainstem abnormality that likely made them vulnerable to sudden death if there was any degree of asphyxia,” Kinney said. “The abnormality prevents the brainstem from responding to the asphyxial challenge and waking.”

The investigators believe these findings confirm that sudden unexplained death in infants is associated with underlying vulnerabilities, and that not all infants who die in compromised sleep environments are normal.

“Certainly, there are compromised sleeping environments that can cause any baby to die, such as entrapment in the crib, but if it’s just sleeping face down, the baby who dies may have an underlying brainstem vulnerability,” Kinney said. “We have to find ways to test for this underlying vulnerability in living babies and then to treat it. Our team is focused now upon developing such a test and treatment.”

Dr. Kinney said  following “safe sleep practices” remained “absolutely important” to prevent babies from “potentially asphyxiating” situations.


  • momofmany

    This does not explain why SIDS is almost unheard of in other countries and almost doesn’t exist is 3rd world countries- where they are exclusively breastfed and sleep with their mothers.

    • Dawn Luttig Novak

      I’d like to know where you got your information. Just because SIDS deaths in 3rd world countries aren’t all over the news, doesn’t mean it’s not happening. Infant death for whatever reason, is much more common in 3rd world countries. I don’t think you’re conclusions are reliable

    • This Girl

      Haha, I was gonna say ‘Because they sleep with their mothers’ But you said it! MY baby slept with me and every time he made a strange move i’d wake up, never will i NOT sleep with any of my future babies. That’s where I feel they are safest.

  • Motherofone

    No it dosent explain that. I dont think breastfeeding has anything to do with it though. There is no proof or facts out there that babies who do not breastfeed or do, die more from sids.And I did cosleep with my boy. Hes about to turn into a happy 1 year old. I think something else is going on. I dont know what but something definitely is

  • Virgie n Dave Buhler

    As parents of a child lost to Sids I find your report very intersting. Was wondering what kind of brain stem adnormalities you are talking about,as we had an autospy done on our daughter n nothing was mentioned. Thank you

  • Rebecca Maker

    This study is nothing new. They have been researching this and coming up with the same conclusion for a long time. The abnormality is in the amount of Serotonin, a chemical produced in the brain stem that helps with heart rate, breathing, and temp control. Here is my question, when are they going to come up with a screening or a test for all newborns for low levels of Serotonin? When are they going to study the risks vs. benefits of treating newborns? As a grandmother of a baby “believed” to have died of SIDS, I would like answers to those questions. My grandson had a low resting heart rate in the hospital, down in the 70’s at 24 hours old. Had I have known about these studies BEFORE he died, I would have demanded further testing. The Pediatrician ordered a chest x-ray and echo cardiogram but nothing more!!!! If all the studies relate back to the same thing, an abnormality in the brain, then why aren’t they finding solutions?

    • Candace

      Rebecca if you read the article it states that they are currently developing ways to test Serotonin levels in infants. Its not instant.

  • Hjone

    it’s unheard of “motherofone” because they lack the U.S. wealth to document let alone investigate when babies die. It’s not because it’s not happening. Infant mortality rates are much higher in third world countries than in the U.S.

  • Michael Griffin

    For all of us who have lost are child to this it will not help lets just pray they get it figured out so no one else has to suffer and go threw this pain of burying a child!!!!!!

  • PAH

    I’d like to see the original publication cited in this article. I can’t find it anywhere and I already checked the Pediatrics website.

  • Jessica Holland

    I lost my almost 6 month old son to SUID in July. With this talk about serotonin levels, I wonder if the Zoloft I was taking during pregnancy has anything to do with his death. I’m pregnant again and I’m on an even higher dose of Zoloft… I’m feeling sick to my stomach now!

    By the way, my son was breastfed, took a pacifier, he slept within arms reach of me and was healthy. Unfortunately he was with a licensed day care provider, grown women with children of her own when the incident happened.

    • Jocelynn Schnell

      Doctors will tell you its safe to take anti depressants, but if you do some research you will clearly see its not.

      I do not advise taking it unless you absolutely have to.

      Wether its connected to sids or not i do not know!

      Not judging. I just thought i would inform you since it didnt look like anyone had.

  • FKhat

    What about surviving adult siblings of SIDS death? Any studies, planned or current to address what, if any, lingering affects a brain stem abnormality may mean to surviving siblings that lucked out and didn’t succumb, or is it being assumed that all children with the abnormalities 1) die of it, 2) outgrow it, or 3) that it isn’t hereditary?

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