Wednesday, February 03, 2010

Sleep Training: Higher Stress, Lower Serotonin May Increase SIDS

By Liz DeMar author of the Hybrid Life

I happened to catch the NBC Nightly News this evening where I heard about the latest development in SIDS research. (1, 2) My interest was piqued even before I heard the full story: How would this compare to research done by Dr. James McKenna? What does it mean for those who share sleep (co-sleepers)? What would be the mainstream media response? According to the study:

“Lower levels of the hormone serotonin may help explain why some infants succumb to sudden infant death syndrome (SIDS).”
I have a bit of experience with wonky levels of serotonin. In my experience with generalized anxiety disorder, my serotonin levels were negatively impacted following a period of extreme stress. Extreme stress. You know -- like the stress that a baby would feel if his parents laid him in the crib and walked out the door. Like the anxiety that would flood his little body as he wailed and waited for them to come back to him. Like the despair he would feel when they did not.

Could this new research possibly support the theory of a link between "sleep training" and SIDS?

This latest study could be an affirmation of McKenna’s position that babies are safest when they sleep within an arm's reach of their mothers, and breastfeed on cue. Serotonin is a hormone that exists primarily in the gut of a human being. It regulates intestinal movement and operates optimally when 'fed' and cared for. (A hungry baby, for example, will have serotonin levels that are off kilter). Serotonin is also highly responsible for other central nervous system functions - the regulation of mood, sleep, muscle movement, appetite, learning and memory. Serotonin works as a calming hormone in the body, while cortisol (a stress hormone) spikes when distressed.

A co-sleeping baby never experiences this rise of stress hormones (such as cortisol) from being left alone to cry-it-out. Rather, a baby sleeping near his mother feels the security of her body, her warmth, her regulatory breath, right beside him. A co-sleeping baby is happy. Research demonstrates that a co-sleeping baby has natural, normal, regulated levels of serotonin. (3, 4)

Unfortunately, that’s not the way that the mainstream media may present the results. Already we see reactions like this from the medical community:
“I think the message is there is something inherently wrong in some of these babies.”
Really? Is there “something inherently wrong” with these babies? Or perhaps something inherently wrong with the way we are being taught to parent...


Turn your crib into a co-sleeper and benefit from sharing sleep!


1) Hannah C. Kinney, MD, professor of pathology, Harvard Medical School; neuropathologist, Children's Hospital Boston. 

2) J. Duncan, et. al. "Brainstem Serotonergic Deficiency in Sudden Infant Death Syndrome." JAMA. 2010;303(5):430-437. 

3) Gerhardt, S. (2004). Why Love Matters: How Affection Shapes a Baby's Brain. Brunner-Routledge: New York. 

4) Sunderland, M. (2006). The Science of Parenting: How today's brain research can help you raise healthy, happy, emotionally balanced children. DK Publishing: New York.



  1. Actually when good morning america presented this research their doctor specifically mentioned cosleeping as a cause of increased SIDs which is against EVERYTHING I have found in the research. I got so mad I had to turn it off.

  2. Nepsi, that's horrible. Especially since there are studies that contradict that. Mainstream media makes me crazy sometimes.

  3. I love this post!!! Despite my desperate lack of sleep for a year, I lovingly co-slept with my son because I not only knew the benefits of doing so but felt that it wasn't natural for babies to be so far away from their parents and so alone. It isn't until very recently that families sleep in separate rooms.

  4. My son is nearly 2 and I still share sleep. I used to have him in the bed and now I use my crib as a side-sleeper. I nurse him and then he crawls into it himself. He crawls back in at some point in the middle of the night to snuggle.

    I will say that I have not had any lack of sleep issues related to this. In fact, my husband and I slept better because we were never dealing with a screaming baby. We wakes up, nurses, and goes right back to sleep. I wish more moms would give this a try. It's pretty amazing.And that's not even mentioning all the medical and emotional benefits of sharing sleep!

    The best part: I get to wake up next to an adorable smiling toddler with his little arms around my neck :)

    Love the post!

  5. One doesn't have to look very far to see cultures where SIDS rates are almost non-existent (mainly Asian ones, where babies are not bedded separately from their mothers/family members). A fabulous book which touches on McKenna's brilliant work, and speaks to how culture can (negatively...) affect how we parent, is Meredith Small's "Our Babies, Ourselves". Highly recommend it !

  6. I do know of babies that have died from SIDS even while sleeping next to their mothers. Very sad. So the search continues for answers... though this does make so much sense - and I cosleep.

    What do you think of the Sprott research on chemicals in crib mattresses?

  7. Great post. Thank you for sharing your thoughts on this.

  8. In nursing school we learned that babies who co-sleep actually have a LOWER risk of SIDS. They stressed that SIDS is NOT the same as suffocation. In SIDS the baby stops breathing for an unknown reason.

  9. So, not to discount Emma's post, wouldn't we see a much lower rate of SIDS in places where parents don't co-sleep? I wonder what the rates are really like. Something to google in the morning.

  10. When as a race are we going to wake up and smell the coffee? - we cannot improve on nature. Babies are meant to be held close, loved and fed when hungry. Anything less is sub optimal (co sleeping is NOT better, it's that everything else is worse) and we should be prepared for sub optimal results.

  11. Jane ~ I'd love to quote you. If this is okay, could you drop a note to and let us know if this would be okay and if you'd prefer to be quoted with your full name or just first? Thanks!

  12. Our newborn is extremely happy sleeping on his own. My wife does breastfeed on demand during the evening, but he has adjusted very well to sleeping on his own and has even found comfort in just resting in his crib. He has also learned to put himself back to sleep as he moves through an infants natural sleep pattern. So when he wakes up in the middle of a sleep cycle and cries we have soothed him without having to pick him up and hold him close.

    I take umbrage with people who insist one way is best. We took the cues from our son. He sleeps better alone than in someone's arms. Maybe THAT is what more research should be focused on. Not that one way or the other is best, better or the only way.

  13. Isn't it interesting that when a baby wakes and cries during the day, the average parent goes to pick up and console them. The infant is fed, changed or simply held in order to provide comfort. However during the night when the parent is tired, they decide to allow the baby to cry it out. Somehow at night all rules are off and this baby is now expected to self soothe. What a ridiculous concept. A baby can't console themselves during the night any better than they can at night. All 4 of my children have been co-sleepers and since myhusband was supportive of that concept, it made everyone happy, especially our babies. I do believe parents need to take precaution as to not sleep deep enough that there would be possibility in smothering the sleeping infant and there are many ways to go about that. But, it has been said time and time again that SIDS is caused when a infant stops breathing from an unknown cause, not from suffocation. An autopsy would reveal if a infant dies due to being smothered.

    1. Very well said!!!!

  14. I use to be afraid to co-sleep with my little one but after she was born I decided to give it a try. (I was afraid I would squish her in the night or something) The only time she is in her crib is when me and husband take a shower and for feeding its super easy no having to wake up all the way and make a bottle or go pick her up. I remember hearing from one of the news channels how co-sleeping is bad for baby. Its sad how twisted the news can get.

  15. Vaccination is the true leading cause of SIDS, not co-sleeping.

  16. @Paula - I think you meant "wouldn't we see a much lower rate of SIDS in places where parents DO cosleep"? And, in fact, we do. In nations where mothers and babies sleep by each other all the time, there are very low SIDS rates, and several cultures (where mothers nurse on cue and sleep within an arm's reach of baby) do not even have a term for "SIDS" because it is so unheard of.

    Sleep Research Resource List:

    Sleep Training/CIO Research List:

    1. i never heard about SIDS or baby died because we sleep with our baby in my country. what do you think of those poor country who has no other room for the baby to sleep so they sleep with their baby. I can't sleep if i will not sleep with my baby.

  17. I love this - I've thought this for awhile, too...also the closeness that attachment parenting engenders, so you are RIGHT there and can immediately tell if something is wrong with your baby.

  18. What a great post! We co-sleep with our three-month-old and love it. I don't see how it's better to start a brand new person's life by immediately teaching him that he's alone in the world and must comfort himself because Mom and Dad won't always do it for him. To me, that's sad.

  19. My friend's baby died of SIDS and he was in the caregiver's arms when he stopped breathing. She was very well versed in CPR, a minister's wife who was visited by friends at the time (several witnesses). And like every SIDS story I've ever heard, he recently had the DTaP. Also like every SIDS story I've ever heard, he screamed and cried that eerie vaccine injury cry for two weeks before he died. The doctors called it "colic". Oh I get so mad when I think about it!!!

  20. I agree i think most SIDS cases are vaccine injuries. Tell me why you have a medical community that has a solution to everything except babies randomly dying in their sleep usually at 2 months and 4 months when SIDS cases peaks and this is the time they are overloaded with vaccines. Hmmmmm odd... i think not. They know what it is. Its the brain swelling. Same thing with colic which cannot be explained and some just say babies cry and cry for no reason? UM NO. The baby is crying and crying from his brain swelling and swelling. I have never seen a unvaxxed baby with colic. Coincidence? I think not!

  21. @Jackie. I agree with many things about SIDS. My daughter is nearly 3 and still cosleeps and nurses. We practice AP. We do modified vax schedule. She had colic from a few days old till about 5 months. Colic is a result of gas pain, nothing to do with the brain. I read recently that the gut flora of csection babies and vaginal birth babies are very different. My daughter was born via emergency csection- that's what I believe contributed to her colic. I know it couldnt have been due to vax because it started before she ever got any. Besides, my DD always felt better after some gas relieving remedy (we liked Colic Calm because it's homeopathic).  I tried changing my diet, using Probiotics, etc. The only thing that seemed to take care of it for her was time- time for her digestive system to mature.  

  22. I think that, if the truth were told, we would find that a lot of (if not most of) the cases in which co-sleeping babies died in their sleep were caused by suffocation.

    And, to disprove the theory that a co-sleeping parent is risking rolling over on their child, I would bet that most of those co-sleeping suffocation cases were caused by parents who were under the influence of narcotic pain medications (if you're not used to them they make you super sleepy and they're commonly given after childbirth), alcohol (how many moms with PPD, or even without it, have a few drinks to take the edge off in those early months while adjusting to a new baby), benzos, etc.

    I also have known quite a few moms who lay young babies to sleep on their stomach because "they sleep better that way". And I've also known even more mothers who smoke around their babies, even in the bedroom (I'm not picking on smokers here, I am a smoker, but I don't smoke in my house or car or anywhere around my children, and I shower and change into smoke free clothing before co-sleeping). Perhaps the media should focus on drug and alcohol abuse and smoking while co-sleeping instead of just co-sleeping.

    Oh and thank you so much for this! I'm going to show this to pretty much everyone I know!

  23. @Jackie and @Tammy. My DD was born naturally at home and has never received a vaccination. She suffered from colic for the first 3 months of her life. It disappeared quite suddenly. I believe colic is the result of human babies' being so underdeveloped when they are born compared to any other species. The gut is still developing, which results in a lot of gas pains and discomfort. Just my own opinion. DD is now 8 months old and is the happiest little lady. We still cosleep and bf like it's our JOB. :-)

  24. What happens when baby doesn't learn to sleep longer despite nursing on cue, sleeping with mama and being picked up the minute they cry?

    I'm not asking this as an offensive question, but this literally happened to me. Months went on and my own health was decreasing at such a rate that I actually ended up in the ER with stress related heart issues because I wasn't getting enough sleep. (son waking ever half hour to hour during the night). I didn't practice CIO, but I did do a little gentle sleep training so I could get healthy...and I did. Baby started sleeping a little longer and had a more regulated day/night schedule after that.

    I know there is so much debate about this subject...but I am honestly curious what people tell mama's who's health is failing due to lack of sleep. Because it does happen, and like me can actually become life threatening if it doesn't change.

    No one person's needs are greater than another. If mama isn't getting her needs met with decent sleep (even sleeping right next to baby) then that's not good either. I just wonder how come there is so much focus on the baby and not much attention paid to the mama.

    I'm a stay at home mama, and I'm sure many here, not only do I nurse around the clock, change diapers, soothe a fussy baby...I also do the laundry, clean the house, cook the meals, tend the gardens and look after my husbands needs as well because he works 50-60 hours a week to support us. There aren't any friends or relatives that can help out (as many suggest) so, where does a mama's health fit in here when she's got so much to do?

    I totally disagree with leaving a baby to CIO until they fall asleep, but there are other more gentle methods of getting baby to sleep and getting them on a more efficient pattern so both mama and baby are eased. I think often times the CIO method is lumped into all the other methods that don't cause brain damage or failure to thrive but these other methods aren't tested on a singular basis.

    Anyway, Just wondering if I'm the ONLY mama that AP parenting (for sleep) didn't work.

    1. There are several things to try instead of sleep training in this situation:

      1) make sure the room is dark (use black out curtains if needed). Babies' melatonin is easily disrupted by light, so it must be dark during sleeping time near mom.

      2) turn a fan on at the end of the bed (not blowing on baby). This mimics the sounds of fluids inutero and helps everyone sleep more soundly and not wake up every time there is a small noise or movement.

      3) Put two sleeping surfaces together (2 mattresses on the floor, or side-car a crib) so that there is enough room for baby to have his own sleep space within an arm's reach of mom. She can move away a bit after baby falls asleep and he will not smell her or feel her as powerfully and be reminded to nurse as often (although he does still need nourishment through the night during his first year or so of life).

      4) roll up a receiving blanket and turn it into a U shape above baby's head. This gives just the right amount of sensation to know something is there, and it soothes baby without being a risk (as a pillow would be before baby can roll).

      5) after baby can roll over back and forth, let baby sleep in any position s/he sleeps best - for many, this is on their side or their tummy.

      Just some ideas that I've learned along the way from other baby sleep experts and I also had a baby who woke every single hour for his first year of life to nurse, and every 3 hours for his 2nd year of life... Some of these things (when implemented) helped us get through (for my own health). I am proud and happy that we never used any form of forced night weaning or sleep training and he still was sleeping through the night on his own by the time he turned 3. :)



Related Posts with Thumbnails