FAQ – Safe Sleep in Pregnancy

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FAQs About Safe Sleep in Pregnancy

Thank you to our partners at Tommy’s for providing the basis for this detailed FAQ about the #SleepOnSide campaign and safe sleep in pregnancy.  As always, feel free to contact us with any additional questions.

In the third trimester our advice is to go sleep on your side because research has shown that this is safer for baby. This includes night sleep and day time naps.

Can I sleep on my back during pregnancy?

Research has shown that in the third trimester (after 28 weeks of pregnancy) going to sleep on your back increases your risk of stillbirth. As the link has now been shown in four separate research trials, our advice is to go to sleep on your side in the third trimester because it is safer for your baby. The advice relates to any episode of sleep, including:

  • going to sleep at night
  • returning to sleep after any night wakenings
  • day time naps.

We don’t want you to become anxious about this. If your pregnancy is uncomplicated your risk of stillbirth is low (1 in 200 babies are stillborn). Going to sleep on your side will make it even lower.

How reliable is the research?

The research linking going to sleep on your back to stillbirth is very reliable. Four case control research studies (in which information from women who have had a stillbirth is compared with information from women who have not) have been carried out into maternal sleep position and stillbirth and all have shown that there is a link.

This new study is the largest one yet into maternal sleep position and pregnancy. It is the fourth case control study confirming the link between supine sleep and stillbirth.


The researchers interviewed over 1000 women about a range of behaviors, including sleep position: 291 women who had a stillbirth at or beyond 28 weeks, compared to 735 women who had not.

Comparative studies and campaigns

In the 80s there were seven case control studies that spotted a link between infant sleeping position and cot death, but there were years of silence until a high profile case was in the media.

A public health campaign was launched telling mothers to stop putting babies to sleep on their front. It reduced SIDS figures by around 80%.

Now it is common and uncontroversial to tell women that their baby should sleep on their back. We want the phrase ‘Go to sleep on your side in late pregnancy’ to be seen in the same way.

What if I wake up on my back during the night?

The research has been focused on position going to sleep, not position during the night. If you wake up on your back, just settle back to sleep on your side.

We cannot control our position when we are asleep and a large bump is likely to be uncomfortable enough to prevent you from being on your back for long during the night. We also know that the position we go to sleep in is the position we spend the longest amount of time in during the night.

What could cause the increased risk of stillbirth?

Sleep position in the third trimester is important because if you are on your back the combined weight of baby and womb puts pressure on other organs in your body.

Researchers do not know for certain what exactly is causing the increased risk of stillbirth, but we already know the following, which could play a part:

  • When sleeping/lying on your back the baby and womb put pressure on the main blood vessels that supply the uterus and this can restrict blood flow/oxygen to the baby.
  • Further recent studies have shown that when a woman lies on her back in late pregnancy (compared to lying on side) the baby is less active and has changes in heart-rate patterns. This is thought to be due to lower oxygen levels in the baby when the mother lies on her back.
Does it make a difference which side I sleep on in pregnancy?

There are many websites that tell you that the left side is best to sleep on during pregnancy. This is for the following reasons:

  • One of the smaller research studies, from Auckland, New Zealand, showed that women who sleep on their left side on the last night of pregnancy halved their risk of stillbirth compared to those who slept on their right. However, the same finding has not been seen in any other trial (there have been three other published research studies since then).
  • Sleeping on your left has been shown to help your kidneys to get rid of waste products and fluids from your body.

Therefore, while sleeping on your left side has not conclusively been shown to reduce your risk against sleeping on your right, there are reasons that you might choose to do so.

Tips for sleeping on your side in pregnancy
  • Put pillows behind you to prevent falling on your back. It won’t prevent you being on your back for certain but is likely to make it more uncomfortable.
  • If you wake up for any reason during the night, check your position and go back to sleep on your side.
  • If you are likely to nap during the day pay the same attention to sleep position during the day as you would during the night.
Is it harmful to sleep on my stomach in pregnancy?

In the early days of pregnancy it is fine to sleep on your stomach. Your bump will not start showing until the second trimester and sleeping on your stomach is unlikely to be uncomfortable. In the third trimester, you will have a large bump and it is very unlikely that you would choose this position. However, if you do wake up on your stomach, don’t worry, just roll onto your side.

Doesn’t everyone know to sleep on their side already?

The short answer to this is ‘No’. Not everyone knows to sleep on their side already. Research into current sleep position shows us that 10% of women (that’s more than 60,000) in the UK go to sleep on their back in late pregnancy[1].

Yes, some women are getting this message already but until now, professionals and the public haven’t fully known why and how important it is. It has not been prioritized as a message for midwives to tell women and many pregnant women do not hear it at all.

Some professionals have been telling women that sleeping on their side is better because there is a major artery (the vena cava) running down the spine that supplies oxygen to the placenta. When women lie on their backs in late pregnancy, this artery can be compressed by the weight of the womb, which reduces the flow of blood. Women fainting has been, until now, midwives’ primary cause of concern.

No one sleeps on their back in late pregnancy, it’s so uncomfortable!

As explained above, this isn’t true for all women. Around 10% of women currently sleep on their back in the last three months of pregnancy.

I have Symphysis Pubis Dysfunction (SPD) / Pelvic Girdle Pain (PGP) so sleeping on my side is really hard

For women with SPD this can be very hard advice to follow. But the important thing is that you’re not lying flat on your back as this is what the research is related to.

There are other ways you may be able to achieve this without having to be completely on your side. In labour,  midwives recommend/NICE recommends that women lie at a tilt of at least 30 degrees to ensure babies are not lying on the big blood vessels, so that may be a solution if lying on the side is painful.

If you can find a way to get comfortable on your side, for example with a pillow behind your back or in a v-shape, and perhaps one supporting your legs, then that would be ideal. What you want to do is to try to keep your legs level. If your top leg is dipping down on to your bottom leg, it is likely to cause pain, but if you keep them level using a pillow you might find it easier to sleep on your side.

However, there is a balance between sleeping in the safest position and getting as much good quality sleep as possible, which isn’t always easy in late pregnancy even without SPD/PGP.

We’d encourage you to seek a referral for physiotherapy if you’ve not done that already; speak to your midwife and they should be able to help with this.

I’m pregnant and this campaign has made me anxious

Firstly, we’re really sorry if this campaign has made you feel anxious. It is not our intention at all to worry women.

Remember that this study focuses on the position you go to sleep in, which is the one you will spend most of your time in. As long as you’re starting on your side and turning back over if you wake up on your back, then you are doing everything you can to reduce your risk.

If you do wake up on your back, it’s OK. Just turn over again onto your side and settle back to sleep. The fact that you’re waking up on your back probably means that you were uncomfortable, so it’s unlikely you have been in that position for long.

If you’d like to talk about how you’re feeling please comment below, email us or give the Tommy’s midwives a ring on 0800 0147 800. (In the US, please contact Star Legacy Foundation here.)

Why are you scaremongering? / Women have been having babies for years without endless advice

We would never intentionally scare women or make them feel anxious on purpose. However, we cannot hold this evidence-based information back from women as it has clear advice on how to protect their baby. This is the fourth study confirming the link between going to sleep supine (on your back) and stillbirth, and we believe women have the right to be well-informed. We will never scaremonger, or give out information that is unreliable.

We have worked on this campaign in collaboration with the researchers, pregnant women, women who have suffered a stillbirth and health organizations such as the royal colleges and the NHS to ensure the message is delivered in a non-threatening way.

Although women have had healthy live babies for years without this information, unfortunately, many babies have also been stillborn. Currently around 9 babies are stillborn every day in the UK and if there is anything we can do to stop even one more family from going through that most terrible of heartbreaks, then we will not withhold that information.

It is estimated that if every woman in the UK who currently sleeps on her back in late pregnancy started sleeping on her side, up to 130 babies a year could be saved. This would reduce our unacceptably high stillbirth rate by about 3.7%.

Read more about the MiNESS research

It feels like you are blaming mothers who have experienced stillbirth

We would never blame any woman for a stillbirth, and throughout the development of this campaign we have worked with women who have experience of stillbirth to make sure that they don’t feel like this campaign will cause blame. Everyone we spoke with who had a previous stillbirth told us that it was a very important message to deliver to pregnant women.

We work closely with women in the baby loss community, all of whom told us that ‘going to sleep on your side in late pregnancy’ is a vital message to get out to women. And that it is important not to hide the link to stillbirth.

This is the fourth study confirming the link between going to sleep on back and stillbirth and we believe women have the right to be well-informed.

Michelle from Dear Orla explains:

‘As someone who has experienced first-hand the trauma of stillbirth, I was invited to come and review this campaign when it was being pulled together. There is an uncomfortable push and pull about new research and campaigns such as this – you hope from the bottom of your heart that no one else should have to suffer the pain of losing their baby, yet you feel an overwhelming sense of sadness and anger that your own baby wasn’t afforded the same opportunity. I also went in with a dread that I would somehow be left feeling that Orla’s death was indeed my fault, and that I would need to live with proof of this blame for the rest of my life. But Tommy’s really understand this, which is why they ask real people with varying pregnancy experiences for their feedback.’

Read more from Michelle and follow Dear Orla on Instagram

I slept on my back. Is that why my baby was stillborn?

Unfortunately, we can’t tell if this contributed to your baby’s death. Researchers can’t say for certain why the risk is increased, though there are several theories which you can read about here.

The most important thing to remember is that this research is NEW. The research paper the campaign is based on was published on 20th November 2017. The previous paper on this topic was published a couple of months ago in July 2017. Until that point, the public and the professionals who care for them did not have conclusive evidence about the strong link between sleep position and stillbirth.

Therefore, it cannot be your fault and you are not to blame.

Tommy’s exists to save babies’ lives and find answers for the families of the babies that we haven’t been able to save. This research, and any reduction in stillbirth rates that it brings, would not be possible without the support of parents who have experienced loss and their determination to make a difference. We thank you from the bottom of our hearts, and are here for you if the news has been heavy or upsetting.

Our team of midwives are available online and on 0800 0147 800, Monday to Friday, 9am to 5pm. If you need any support, or if you have questions please get in touch. (In the US, please contact Star Legacy Foundation here.)

How can I help you share the message?

There are two simple ways you can help us spread the #SleepOnSide message:

  1. Word of mouth – tell friends, family members and colleagues about the campaign. If they’re not pregnant now, they might be one day or know someone who is.
  2. Share our campaign film on FacebookTwitter or download it for Instagram. Don’t forget to use #SleepOnSide!

If you’re a maternity healthcare professional, please download the film for your waiting areas and share this message with the families you care for.  (In the US, please also distribute Star Legacy Foundation’s free Parenting in Pregnancy brochure, which covers safe sleep practices as well as other information and resources for expectant families who want to do all they can to promote a health pregnancy and birth.)

[1] Heazell AEP, Li M, Budd J, Thompson JMD, Stacey T, Cronin RS, Martin B, Roberts D, Mitchell EA, McCowan LME. Association between maternal sleep practices and late stillbirth – findings from a stillbirth case-control study. BJOG 2017; https://doi.org/10.1111/1471-0528.14967.

[2] Lesley ME, McCowan LME, Thompson JMD, Cronin RS et al (2017) Going to sleep in the supine position is a modifiable risk factor for late pregnancy stillbirth; Findings from the New Zealand multicentre stillbirth case-control study. PLOS One https://doi.org/10.1371/journal.pone.0179396

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