Medical examiners have replaced the term SIDS with “undetermined” to reflect that they don’t really know why infants die suddenly. But parents can still take precautions to keep babies safe.

On his last night, Daxon Stankey went to bed happy and content, just like any other night. At 10 months old, he was busy all day, crawling and happily tucking into any food he was offered. The mere sight of a snack was enough to make the baby grin. It wouldn’t be long before he started to walk—he was already trying.

Because his mom, Krystal Needham, was trying to wean Daxon off breast milk, her boyfriend volunteered to put her son in his crib for the night. When he came back downstairs, he reported that Daxon had settled on his belly. “I didn’t really worry about it,” says Needham. “He always rolls onto his tummy anyway, even if I put him down on his back.”

When Needham woke up in the morning, her first thought was that it seemed late. She went into Daxon’s room to check on him. Lying in the middle of his crib, fists clenched, her young son was lifeless.

“He was face down and he was gone. It seemed like he had been for hours,” recalled Needham, who, five months after Daxon died, is still wracked with grief at her last memories of her little boy. She’s still trying to make sense of his death. “He didn’t suffocate. He could turn his head, he could roll over, he was almost walking,” she says. “His face looked smushed, like something out of a nightmare. He didn’t look like my baby at all.”

Later, when the local Calgary medical examiner called, Needham asked the pathologist if Daxon had died from SIDS—sudden infant death syndrome. The term SIDS has been used since the late 1960s to describe the unexpected deaths of babies who appear to be healthy and developing well but, for no explicable reason, go to sleep and do not wake up. They stop breathing at some point during their sleep. And while researchers warn against taking risks that can make it difficult for babies to breathe—such as having bumpers, stuffed animals or too many blankets in the crib, smoking in the house, keeping the temperature too hot or cold, and putting babies to sleep on their tummies or sides—the actual cause of death is usually impossible to determine with certainty.

SIDS is considered the leading cause of death among babies aged one month to one year old in Canada. Other common terms for the phenomenon include “crib death” or “sudden unexpected infant death.”

But, when Needham asked about SIDS, she was told the term is no longer in use. Instead, Daxon’s death would be classified as “undetermined.” The word immediately made Needham uncomfortable, as if authorities thought she was responsible for Daxon’s death or had done something wrong, she says. Across the country, dozens of bereaved parents who have also been told their infants’ sudden deaths are due to “undetermined” causes are struggling with the same worry and confusion.

Use of the term is part of a cross-country shift by coroners and medical examiners who have decided to stop using SIDS to classify sudden and unexpected infant deaths.

The shift was first suggested in 2010 and, after much research, instituted in 2012, says Lisa Lapointe, BC’s Chief Coroner and chair of the Canadian Forum of Chief Coroners and Chief Medical Examiners. The goal in making the change, says Lapointe, is to improve the accuracy of national statistics related to sudden infant deaths by ensuring all provinces are using the same terminology to classify them. In the past, while some used the term SIDS, others used “sudden unexpected death of an infant” (SUDI) or “undetermined,” making tracking difficult.

“The term SIDS was really introduced so we had some way of explaining why infants died suddenly and unexpectedly where no other cause of death was established at autopsy,” says Lapointe. “Over time, people have come to see it as a diagnosis. But it actually just meant no cause of death had been established,” she explains. “The feeling was, Why are we putting a name to something when, basically, we have no idea why this child died?”

Lapointe says using the term “undetermined” seems to be more accurate. But the word has put many traumatized, grieving parents on edge.

“To see that on paper, it kind of makes you wonder if there’s something that you did wrong,” says Erin Inglehart, a Martensville, Sask., mother whose one-year-old son Nathan died during his sleep, suddenly and unexpectedly, about three years ago. His cause of death was also classified as “undetermined.” “SIDS parents already feel an enormous amount of guilt related to their child’s death,” says Inglehart. “‘Undetermined’ feels like the blame is placed back on the parent.”

Parents also struggle with how to explain a death classified as “undetermined” to their friends and family.

Lapointe says the aim is not to cast suspicion on parents. “There’s never any intention to shame parents at all. We’re always trying to look at what could be done to prevent similar deaths in the future.” Key to that, she says, is moving away from using SIDS as a catch-all term to describe young babies who die unexpectedly during sleep. While some have no identifiable cause of death, others are actually asphyxiated (which can be the result of sleeping on soft surfaces, such as a couch or familial bed, or having too many blankets, stuffed animals or bumpers in the crib). Separating those cases from the truly undetermined cases will narrow researchers’ focus and hopefully improve their chances of one day uncovering the cause of sudden infant death, says Lapointe.

In the meantime, parents need to know that even though the term SIDS is falling out of favour, taking precautions to limit risk factors is still important.

“Infants still die suddenly and unexpectedly for no reason,” says Lapointe. “We know there are some risk factors parents can be really cautious about to help reduce the chances of their child dying.”

Some of those precautions parents can take include putting babies to sleep on their backs in their own crib or bassinet, and not on a shared sleep surface, says Ian Mitchell, a SIDS researcher and professor emeritus of paediatrics at the University of Calgary. Parents should not smoke during pregnancy or in the house. Infant sleeping environments should be free of extra and loose blankets, bumpers, pillows and stuffed animals and of moderate temperature. But in some cases it’s still not enough. “You can’t prevent every case,” says Mitchell. “But we have been able to prevent many cases. The numbers are way down all over the world.” Still, social trends like co-sleeping have led to a small uptick in cases in North America, he says.

Needham, who is expecting another baby in July, says she will take precautions with the new baby but knows her efforts may not guarantee his safety.

“It doesn’t really seem like you can prevent SIDS, but you can prevent suffocation,” she says. “I’m terrified of it happening again and I’d rather know if there’s something I can avoid doing.”

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