June 1, 2026

The Receipts, Vol. 1: The SIDS Myth

One of my consultants called me last week.

“Amanda–I need to talk to you ASAP”

My consultant received a long email from a potential client saying they wanted to start sleep training. They were tired, exhausted, and nothing was working. They were at their endpoint. The one sticking point she couldn’t get over was how sleep training increased the risks of SIDS.

Obviously, working in the baby sleep industry, SIDS is top of mind, always. We are, and have to be, extremely well-versed in SIDS guidelines to protect our clients and ourselves. My consultant and I got on the phone, discussed what the evidence actually says, and we passed it on to our client.

This is not the first time this has happened.

If you have followed BBS for any length of time, you know I am evidence-based to my core. And every single month, it feels like I watch another wildly inaccurate claim about sleep training go viral, and I sit on my hands trying not to comment.

No more.

Every quarter, I will pick one of these myths, do the legwork, pull out the actual studies, and show you the receipts. Hence the name (and YES, it’s a nod to the Real Housewives of Salt Lake City–thanks for asking)

And I want to start with the big one. The one that genuinely scares parents:

“Sleep training increases the risk of SIDS, because babies sleep too deeply and lose their protective night wakings.”

I needed a full 24 hours with this one. I have been in this field for almost a decade. I have heard a lot of bad takes on sleep training. But this one is masquerading as a scientific concern when it is actually scientific garbage.

Here’s the truth: That claim falls apart in three places.

First, the premise. The whole thing rests on the idea that sleep-trained babies sleep “more deeply” than non-sleep-trained babies. They don’t.

(Side note–anti-sleep training folks love to use the fact that sleep training does not decrease wakes as an argument against sleep training all the time. Sleep training will NOT STOP your baby from waking, it just gives them the tools to GO BACK TO SLEEP ON THEIR OWN)

Studies using actigraphy, an objective method for monitoring overnight sleep, consistently show that sleep-trained and non-sleep-trained babies have the same sleep architecture. Same cycles, same arousals, same wakings. What changes after sleep training is not how the baby sleeps. It is how the baby signals. Trained babies still wake. They just don’t need a parent to put them back down.

So if the baby is not actually sleeping more deeply, the whole fear collapses before we even get to SIDS.

Second, the biology. When SIDS researchers talk about arousal deficits, they are talking about biological abnormalities. Serotonin pathways. Autonomic regulation. The wiring that controls how a baby’s body responds to low oxygen. You cannot behaviorally train a brainstem. You cannot adjust a baby’s bedtime routine and change their neurochemistry. The two things are operating in completely different parts of the body. The AAP’s 2022 safe sleep policy lays this out plainly, and sleep training does not appear anywhere in it as a risk factor.

Third, and let’s be very clear.

You can sleep train AND follow every single safe sleep recommendation. The two have never been in conflict. Sleep training is a behavioural process. Safe sleep is an environmental checklist. You can absolutely do both, and you should.

Here is what actually reduces SIDS risk, straight from the AAP:

Back sleeping for every sleep, until baby is rolling both ways on their own.
Firm, flat, non inclined sleep surface. A crib, bassinet, or play yard that meets current safety standards.
Room sharing without bed sharing for at least the first 6 months. This one reduces SIDS risk by as much as 50 percent. Yes, you can sleep train a baby whose crib is in your room. We do it with families all the time.
Nothing in the sleep space. No loose bedding, bumpers, pillows, stuffed animals, weighted sleep sacks, or positioners.
Avoid overheating. Light layers, cool room.
No smoke exposure.
Breastfeeding where possible.
Up to date immunizations.

That is the list. That is what moves the needle. Whether your baby falls asleep with help or independently is not on it, and it never has been.

So what does cause SIDS?

Honestly, researchers are still trying to figure this part out. Right now, the most convincing evidence says SIDS is caused by biological vulnerabilities that babies are born with, not something that develops from how they fall asleep. Dr. Hannah Kinney’s work at NIH identified abnormalities in brainstem serotonin pathways in babies who died of SIDS, specifically in the regions that regulate breathing, arousal, and the body’s response to low oxygen. Harrington et al. 2022, published in eBioMedicine found that an enzyme called butyrylcholinesterase, which measures autonomic nervous system function, was significantly lower at birth in babies who later died of SIDS. Frelinger et al. 2024 in Scientific Reports extended these findings into peripheral blood, pointing to a broader dysregulation of serotonin and related signalling pathways that may one day be detectable in a simple test. A 2024 study published in JAMA Neurology used next-generation genetic sequencing to identify undiagnosed brain inflammation and viral infection as a contributor to brainstem pathology in some SIDS cases.

The thread running through every single one of these studies is the same: SIDS risk is present at birth. It is biological, not behavioural. So far, there is no plausible way that sleep training, which is a learning process that operates at the level of conscious behaviour, could create, worsen, or interact with the deep neurobiological vulnerabilities researchers are now identifying.

What I want you to know:

You are not putting your baby at risk by helping them sleep.
You are not overriding their biology.
You are NOT a bad parent.

You are using evidence to make a decision that works for your family. That is the receipt.

Whether you’re at the beginning stages of sleep training with your baby or you just want to improve your mental health as a parent, the sleep consultants at Baby’s Best Sleep are here to help.