Infants wake up more today than they did 40 years ago

Thousands of babies are saved per year with the 1992 back-to-sleep recommendation. But at what cost? On back-to-sleep, breastfeeding, and ways you can get better sleep while minimizing risk of SIDS.

My oldest and youngest child. The middle child, who slept the most lightly, is not pictured as he was sleeping in his blackout-curtain-encased bottom bunk.

First, some community events!

Community events round up

• Baby and Me Sewing at Sequoia Fabrica - Make a lovey with your baby in San Francisco's number one baby-friendly makerspace! They even provide baby carriers if you don't have one of your own to use while sewing.

• Work n play at Manny's café - Every Tuesday at 11:30am. The café has a kids area. Parents read, write, or just chat while kids play.

• Parents' Circle at The Commons - Every Saturday 10:30am-12:30pm. Weekly review & problem solving in community. Venue has a kids corner in the same room, and parents pool $20 each (bring as many kids as you want) for high school babysitters. Drop in anytime during the event.

• Note that All Ages Roller Skating at Hayes Valley Playground is on hold while the community center is closed. It will be back Monday September 9th! In the meanwhile, check out Last-Saturday Roller Skating at Koshland Park on August 31st from 6-9pm!

I also wanted to take a moment to highlight our two recently posted community spaces.

• Dogpatch Hub: A freshly renovated community space with SO many fun things for kids to play with! Open Tuesday to Friday from 10am - 7pm, and Saturdays from 11am - 4pm

• Aydea Cafe: Eat, caffeinate, and chat with a friend at this SOMA cafe with Tatar food and a kids play space! Open 9:30am to 2pm Tuesday to Friday, and noon to 5pm on Saturdays.

We don't have standing events at these but they have generous open hours and you should check them out with your kids!

The book we are thinking about this week is Optimal Motherhood and Other Lies Facebook Told Us ;)

Now, onto the main article…

My sleepless baby

My first child was born 5 weeks early – a planned C section due to vasa previa – and slept like a dream. We had no schedule and would give him naps whenever he started rubbing his eyes. Once, we took him to a house party and when it got to his bedtime in the evening he fell asleep. We put him in his carseat and he snoozed away through the music and everything.

My second child slept very lightly. Maybe it was because he was born on his due date. Even among babies born "at term", babies born later tend to sleep lighter – an effect that lasts through their first year. Indeed, his younger sister who was born 2 weeks early, sleeps just fine. But for him, after the first two weeks, we struggled. We tried everything to get him to sleep on his back – the thousand dollar smart bassinet, different methods of soothing – only to conclude that the only way he would sleep was on his belly. But every year, thousands of babies' lives are saved from Sudden Infant Death Syndrome (SIDS) because they sleep on their back. SIDS isn't the same as suffocation; the causes are still unknown.

I stressed over this. Rationally I knew that by sleeping baby on his belly we were only changing the risk of SIDS from 0.03% to 0.1%. But I loved my baby completely; any time I looked at him I was sure he was the cutest, bestest baby that ever existed¹, and I knew that if he died, "well there was a one third chance that he would have died anyways whether or not you slept him on his belly" was just not going to make me feel any better. I posted on a parent community group asking – is SIDS really from belly sleeping? Or is it somehow mostly OK if I just make sure there's not any blankets and stuff in the crib? Some parents recommended an oxygen monitor alarm. Kelsey Piper wrote the most helpful comment:

This is something our family agonized over. Babies do sleep better on their belly. The risk of SIDS is probably elevated somewhat, but not very much - as you said, you can still avoid suffocation risks. And it feels like being deprived of deep/restful sleep in infancy might also be bad for a baby (and for the parents, who are unable to get a break). I think it'd be quite reasonable for someone to decide the best tradeoff given their values and priorities is to let their child sleep on their stomach…

My personal thinking is that I'll worry about SIDS only if there are other indications that elevate risk, such as the baby being premature, and during the months of peak risk (I think 2-4 months?) and otherwise I mostly won't make costly tradeoffs for small SIDS risk decreases. But this seems intensely personal and I don't have advice for anyone else besides that it is, actually, okay to balance SIDS risks against other considerations for your and your baby's health and wellbeing.

So we slept baby on his belly with an oxygen monitor alarm, and felt reassured that we had done what was best for our family – both to stay sane as parents (especially for our older toddler), and to minimize the risk of SIDS for baby as much as we could given the circumstances.

Ever since then I've been wondering – how much sleep have parents been losing from the back-to-sleep recommendation? How much parental sleep is lost per baby saved from SIDS? And how much harder is infant care now compared to 40 years ago? 3 years and another baby later, I'm sitting down to do the math.

42,500 hours of parental sleep lost per life saved

I am NOT telling you to disregard the American Pediatrics Association. Thousands of babies' lives are saved every year by their back-to-sleep recommendation alone. My hope is that parents can understand the risks and intentionally make the best decisions for their families, focusing on their goals and joys. After all, a life led by the avoidance of known risks is an unhappy one indeed.

Before we start, let's put some risks into context. The risk of death from SIDS is 0.1% for belly-sleeping babies, and 0.03% for back-sleeping babies. It peaks at 3 months and tapers off at around six months. Not counting birth defects, the second most likely cause of death of infants in the USA after SIDS is unintentional injury, which has a rate of 0.036% as of 2022. For reference, the likelihood of baby dying from a car accident in their first year is 0.003% (ten times less), and the likelihood of children dying from a car accident before they reach adulthood is about 0.06% (double the belly-sleeping SIDS rate but just over half of the back-sleeping SIDS rate). Now that we've conceptualized the size of the risk, let's get to the math:

First, how many more wake-ups do back-sleeping babies do? Kahn 1993 looked at 80 3-month-old babies. Half normally slept on their bellies and half on their backs. (This was right after the recommendation changed so not everyone had gotten the memo yet.) They found that 3 month old babies sleeping on their bellies get 16% more sleep, 40% less wakeups, and -- 43% shorter wakeups! Surprisingly, it didn't matter how the babies normally slept; they ALL slept better on their bellies.

For belly versus back, babies were aroused on average 7 times versus 12. (Not every arousal becomes a waking that requires help; most of the time they go back to sleep by themselves without caregiver help) Total time awake was 35 minutes versus SIXTY THREE. Yep, total time awake is nearly double when babies sleep on their back. Results were the same whether the babies were typically fed during their night wakings or not -- just under half of them were not fed when they woke up in the middle of the night, with "night" very reasonably defined as 9pm to 6am.²

Now to translate this into how much sleep parents are getting. A more recent study, Figueiredo 2017, found that 31 formula-fed babies (presumed to be sleeping on their backs in 2017) woke up 1.65 times per night on average. Assuming arousals lead to wake-ups requiring caregiver help at the same rate, I estimate belly sleepers would wake up 0.96 times.

I used formula-fed babies to do the calculation because back in the 90s only half of women EVER breastfed let alone breastfed exclusively. Given that the Kahn 1993 study was done in a research lab and the total awake time is so small (infants drink from the bottle faster than the breast), I would bet that any night time feedings were done with formula. Another point of evidence is that only about half of the 3 month old infants in the 1993 study required food at all from 9pm to 6pm, a rate that seems unlikely to me if they were being fed breast milk.

Figueiredo's 2017 study looked at 163 babies: 97 exclusively breastfed, 35 partially breastfed, and 31 exclusively formula fed. Looking at the data from when the babies were 3 months, exclusively breastfed babies had an higher average of 5.77 awakenings per 24 hour day versus 4.77 for exclusively formula fed. Their longest sleep of the day was also shorter: 5.27 hours versus 6.5. For the extra waking, half was attributed to the day, and half to the night. Based on another paper, Butte 1992, we can estimate that breast feeding increases average per-waking time from 20 minutes to 30 minutes for the baby, and based on Figueiredo 2017 the average number of night wakings goes from 1.65 to 2.19.

Adults usually take 10 minutes to fall asleep. Putting it all together: Our 1993 formula-fed belly-sleepers wake up 0.96 times per night and take 20 minutes to feed plus 10 minutes for the parent to go back to sleep. Our 2017 breastfed back-sleepers wake up 2.19 per night and take 30 minutes to feed plus 10 minutes for the parent to go back to sleep. So, we're looking at parents losing 29 minutes of sleep per night with the belly-sleeping formula fed baby, versus 87.5 minutes per night with the back-sleeping breastfed baby. This means that at three months old, parents of breastfed, back-sleeping 3 month old babies are waking up an hour more on average than their counterparts with babies who eat formula at night and sleep on their bellies. Of that extra hour, about 26 minutes is from breastfeeding and 34 is from the baby sleeping on their back instead of their belly.

This is for 3 month old babies. How long does this effect last? The breastfeeding differences go away at around 5-6 months, where the main modulating factor becomes parental presence at sleep onset (i.e. whether or not the baby is sleep trained). And based on Figueiredo 2017 the differences aren't really present at 2 weeks old, either - at that time breastfed babies wake up a little more often and spend a little more time sleeping. (My wouldn't-sleep-on-his-back baby actually slept great for the first 2 weeks.) So let's say breastfed babies wake up more than formula fed for only months 3 and 4. The difference between back and belly sleep also goes away at 5-6 months, so I will assume that lasts for only 2 months as well.

Over a two month period, that totals 26 hours lost parental sleep from breastfeeding and 34 hours lost sleep from back-sleeping, per baby. SIDS risk goes from 11 incidents per 10,000 babies to 3 incidents when parents sleep babies on their backs. So on average, about 1250 parents need to sleep their baby on their back to save one baby's life, totalling 42,500 hours of parental sleep lost per baby saved.

What's a parent to do?

Any parent would lose 34 hrs of sleep to save their baby's life. But these are averages. Some parents may have health conditions that mean they do worse on low sleep than others in a way that may harm the baby (epilepsy is an example). Some babies -- like my second -- don't sleep at all on their backs! Surely increasing the risk of SIDS from 0.03% to 0.1% is not as bad as not being able to sleep at all. Not counting birth defects and complications, the second most likely cause of death of infants in the USA after SIDS is unintentional injury.

Parents who choose to sleep their babies on their bellies (or who just want peace of mind – after all even on their backs babies still have 0.03% of dying from SIDS) and have $300 to spare might be able to reduce the risk. It seems to me that if a baby has a form of SIDS that is preventable by waking them up, (and if you, the parent, are easily woken up by an alarm), an alarmed oxygen monitor device would prevent it.³

Note though that it's not a good idea to switch your baby from back sleeping to belly sleeping if they can sleep on their back. Mitchell 1999 found that in New Zealand, SIDS risk is increased seven to eight times if a baby used to sleeping on their back is put to sleep on their belly, compared to if they had been sleeping on their belly all along. This may be because if they accidentally turn their head face down, they haven't had practice turning their face back to the side to breathe.

The other 26 hours of lost sleep are from breastfeeding. I breastfed all of my infants. But I actually regret breastfeeding my first two babies exclusively, and not just because it was a huge hassle when they refused the bottle as I returned to work. My husband loved bottle feeding the babies - without that, he explained to me that it felt like his role was reduced to being handed the baby only when the baby was crying and I had given up. When he fed the babies, he got to see them happy and calm and catch their sleepy reflex smiles.

After the first baby, I swore off pumping (cleaning the pump parts! ughhh), so bottle feeding meant formula. As far as I can tell, there's no benefit to exclusive breastfeeding when compared to partial breastfeeding. I don't mean to start a war, but based on sibling studies, it's also unclear to me if there are any long term benefits at all for breastfeeding in a developed country.⁴ Anyways, we gave our third baby one bottle of formula per day before bed and breastfed her the rest. When she started to complain about the bottle at 2 months old (when the sucking reflex became voluntary), we increased it to two bottles a day, which helped her accept it as a fact of life. As a bonus, family members and friends loved feeding her, too!

Finally, healthcare providers should give parents all of the information they need to make the best decisions for their families. For example it would be great for the American Pediatrics Association to say - if you HAVE to cosleep, here is how you can do it as safely as possible.

If parenting a newborn seems harder now than it did for your parents, know that it's not just the cultural factors mentioned in popular media, such as less family and community support. Babies literally wake up more than they used to!! My wish is for you to feel at peace with your parenting decisions so you can fully enjoy all the smart and cute and funny things that your kids do as they grow up. ♥

P.S. This post is based on my viral twitter thread. You can read the original here.

1. This also happened with my other babies. :)

2. Don't you hate it when people say the baby "sleeps through the night" but mean only 12am to 5am? It's like grade inflation but for babies and sleep.

3. I should note that while the oxygen monitor gave ME peace of mind, my husband thought it was useless. Your mileage may vary, I suppose!

4. Further reading from The Atlantic https://www.theatlantic.com/magazine/archive/2009/04/the-case-against-breast-feeding/307311/