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Welcome to our 18th live chat with sleep scientist Helen Ball, who has been studying infant sleep for almost 20 years. Her main focus has been on how parents manage night-time care and why they make certain sleep choices for their infant, which has led her to do lots of research on bedsharing/co-sleeping and the relationships between sleeping and feeding. She has also looked at how parents understand safe sleeping guidance for SIDS reduction and her work has informed a bunch of statements, policies and recommendations by different organisations, both in UK and around the world.
Q: I wondered if you had looked at how much sleep infants need and whether you found that varied a little or a lot from one baby to the next.
Helen: This is a question we have looked into and have covered on our infant sleep info website. The quickest answer to your question is to point you to this graph (Fig. 1), which shows what the wide range of normal sleep looks like for babies of different ages in a host of studies. Basically, the range for babies 0-2 months old is anywhere from 8 to 22 hours a day!
Q: Wow! Some variation. So do you basically observe that enough to consider it normal?
Helen: Yes, the normal variation is huge in early infancy — as time goes on you can see the range narrows and the mean sleep values become more consistent, but at the beginning baby sleep is hugely variable.
Q: We found that both our children sleep better on their tummies. With no other risk factors (and following feet to foot), what is the increase in risk of SIDS?
Helen: Many babies sleep better on their tummies! Studies into arousal mechanisms show that these are blunted when babies sleep prone (tummy down). On average, across all the case control studies done from 1970 to 2004, the prone position increased SIDS rate over 4x.
Q: Is that dependent on age?
Helen: Peak age for SIDS is 2-3 months. Past that age the occurrence declines dramatically. Once a baby can roll independently there is no increased risk.
Q: 4 times increase may be large or small depending on scale. What is the baseline risk, one in 100, 1000, 10000?
Helen: UK general SIDS rate is 1 in 3000, but it is important to remember that this is an average across all the possible scenarios (e.g. smoking, head covering etc). If you don’t do any of these, your baby’s risk is lower.
Q: Could you tell us more about arousal mechanisms? Are they survival mechanisms?
Helen: Yes, a low arousal threshold means a baby wakes from deep sleep to respond to most ‘stimuli’ (airway covering, pressure from a bed-mate, etc). Several factors increase arousal threshold during infant sleep such as prone position, swaddling, formula feeding etc.
Q: Maybe you could also tell us a little about those other factors. Our health visitor seemed to say to me that smoking and overheating were the most influential.
Helen: The factors that are considered the biggies are sleep position, smoke exposure (especially in pregnancy), and unsafe co-sleeping. The mums we have interviewed rarely follow the guidance to the letter – many people think the factors can be traded off against each other. For example, if I go back to sleep, feet to foot, I am ‘cancelling out’ the effect of smoking!
Q: One thing that annoys me is the advice around co-sleeping. I read up on everything and concluded that safe, planned co-sleeping was actually protective against SIDS. And also it made a lot of sense to me since it seemed most comforting for the tiny baby. And yet, a lot of official advice is just a blanket recommendation against co-sleeping. What did your research find about this?
Helen: This is the topic we have studied the most, and in a nutshell the context is everything. How it is done and why dramatically affects whether it is associated with an increased risk. The blanket advice approach is changing, do you know about the latest NICE guidance for health professionals? They are encouraged to discuss co-sleeping and individual circumstances rather than giving blanket advice to not do it.
Q: Aren’t those co-sleeping SIDS deaths mostly from ‘falling asleep on the sofa because feeding in the middle of the night and exhausted’?
Helen: Yes, 90% of co-sleeping deaths involve what we would call hazardous co-sleeping (sleeping on the sofa, or with a smoker, or after consuming drugs/alcohol). But most people who want to ‘ban co-sleeping’ don’t think any of that matters, because it isn’t an important or valued behaviour for them. It is valued by cultural minorities and breastfeeding mothers, not the people who (previously) made up the guidance. This is changing though, I am glad to say.
Q: So is the blanket recommendation against co-sleeping a precautionary thing, to make sure the unsafe practices are stopped (even if it’s at the expense of the safe ones)? A bit like fabric manufacturers setting blanket guidelines just to be on the safe side, even if using certain products would be ok if done properly?
Helen: Yes, I think that is exactly it. The logic is that telling people to put babies on their backs worked as SIDS declined dramatically. We know about 50% of current SIDS deaths happen when co-sleeping, so if ‘we’ tell people to avoid co-sleeping there will be another dramatic decrease. But we would argue it isn’t so simple!
Q: Do you know if any research has ever been done into the difference between cloth nappies and disposables?
Helen: I don’t know of any research into this in the UK, but I remember nappy type being mentioned in a paper from Thailand not too long ago.
Q: Do you know where the 6 months in the same room guidelines come from? Is that SIDS too? And if so, why 6 months?
Helen: The 6 months in same room guidance is because some of the SIDS case control studies have found increased risk when babies sleep in a room on their own.
Q: Has any research been done on the best way to get the baby to sleep? I feel as though we fight to get ours to bed and I wonder if we’re not consistent enough at sticking to times and routines. Everything we do is baby-led but I am thinking that at 6 months she may benefit from knowing what’s going to happen.
Helen: Babies benefit from some degree of predictability – for example, cues that help them anticipate what’s happening and when, but I am not an advocate of rigid scheduling. Responding to her sleep cues would be my approach, but also devising little strategies that help her wind down, relax, and associate certain things with sleep. With one of my daughters I (accidentally I think) conditioned her to fall asleep when I stroked her forehead. I think I just started doing it as a way to relax her and encourage her to close her eyes, but got to a point where if I did it her eyes would roll back in her head and she would drop off!
Q: Have you done any research on “sleeping through the night”? It seems to be a big thing for people and lots of my friends have babies that do it. I bed share with my little girl (21 months) and she wakes maybe twice. How normal is night waking?
Helen: A lot of people seem to have friends whose babies sleep through the night, but I don’t think many of those friends are completely truthful! Studies that have looked at sleep consolidation (putting several sleep cycles together into a prolonged bout) find that about 50% of babies start doing it around 3 months. Another quarter start to do it by 5 months, and the remainder don’t start before a year. Those that do start ‘early’ don’t keep sleeping through consistently and many revert to night waking. Also, breastfed babies continue waking in the night for longer than formula fed babies although both groups actually get the same amount of sleep!
Q: It’s my understanding that naps are important for cognitive development. If my daughter has an hour after lunch though it can be 9 o’clock or later before I can get her to sleep at night. Is there much research about whether this is a sign to cut out the nap or just go with a later bedtime?
Helen: Naps seem to be important at least until the age of 2 and for some children 3 or 4. There was an interesting study last year in US about bedtime resistance. After doing all sorts of tricks with toddlers like shutting out every tiny chink of light in the bedroom to get kids to sleep at bedtime, the researchers found that if the kids melatonin (hormone that promotes sleep) wasn’t high enough at the supposed bedtime nothing would induce sleep no matter what. So they recommended parents simply make the bedtime later and work with the child’s normal circadian rhythm.
(Discussion with one person saying they’d love their child to go to sleep and 9pm, but 11pm is more common!)
Q: So how do we increase melatonin at the correct time?
Helen: That is completely consistent with the day length at the moment. Twilight promotes melatonin production!
Q: I have also been blaming the late evenings. But does that mean he’ll sleep all the time in the winter?Helen: people generally sleep more in the winter, but the effect of artificial light and screen lights are big disruptors in present day.
Q: Everyone seems to agree that around 16 weeks is a terrible spell for sleep regression and disturbance. Have you observed that and is there an explanation for it?
Helen: Yes there is increasing evidence that sleep development doesn’t happen in a smooth and linear fashion but in leaps that can go backwards as well as forwards!
Q: What about the kids that clearly need a nap, but refuse to go? I’d be happy for mine not to have the nap, if the effects didn’t become apparent at about 4 pm.
Helen: If they clearly need a nap (e.g. sleep pressure build-up is affecting their behaviour) then something is making them want to over-ride that urge. This may be daylight/sunshine, or too much interesting stuff happening they might miss if they nap. Perhaps making it dark and boring will do the trick.
Q: If we let a bunch of infants of similar developmental stage and sleep requirements go all Lord of the Flies, would they all sleep at the same times?
Helen: Not necessarily, we all have different propensities for sleep that seem to be inherent (eg genetic or epigenetic) as well as developmental related. Some of us tolerate sleep pressure better than others, and some have more regular circadian rhythms.
Q: Should I let my baby sleep on me during the day to ensure she gets enough sleep? (She wakes after 5 minutes if I put her down)
Helen: how long do you currently hold her before you put her down?
Depends, sometimes 5 minutes after sleep, sometimes 10. I try to wait for the deep sleep. She has been asleep on me for 2.5 hours now and would still wake if I moves her!
Helen: Normally it takes babies 20-30 mins before they drop into deep sleep (they go into REM first, which is different from adults). So try waiting that long before moving her, but not so long she comes out of deep sleep again (60 minute sleep cycles are typical in small babies).
I will try to do that. Does the same apply if she falls asleep feeding?
Helen: yes, it does.
All: Thank you so much for coming Helen, this has been fascinating!
Helen: you are very welcome, this hour flew by! Thank you for all the great questions and remember to visit the infant sleep info website, tell your friends and join us on Facebook!