Sleep position in pregnancy Q&A

In the third trimester of pregnancy going to sleep on your side has been shown to help prevent stillbirth.

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.

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 have long hair, try tying it in a low bun, which may make it uncomfortable to sleep on your back for any length of time.
  • 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.

If you're finding sleeping on your side difficult because of SPD/PGP, try these tips.

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.


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. BJOG2017;

Stacey T1, Thompson JM, Mitchell EA, Ekeroma AJ, Zuccollo JM, McCowan LM.
Association between maternal sleep practices and risk of late stillbirth: a case-control study. BMJ. 2011 Jun 14;342:d3403. doi: 10.1136/bmj.d3403.

Gordon A1, Raynes-Greenow C, Bond D, Morris J, Rawlinson W, Jeffery H. Sleep position, fetal growth restriction, and late-pregnancy stillbirth: the Sydney stillbirth study. Obstet Gynecol. 2015 Feb;125(2):347-55. doi: 10.1097/AOG.0000000000000627.

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

Jeffreys RM, Stepanchak W, Lopez B, Hardis J, Clapp JF, 3rd. Uterine blood flow during supine rest and exercise after 28 weeks of gestation. BJOG : an international journal of obstetrics and gynaecology. 2006 Nov;113(11):1239-47

Khatib N, Weiner Z, Beloosesky R, Vitner D, Thaler I. The effect of maternal supine position on umbilical and cerebral blood flow indices. European journal of obstetrics, gynecology, and reproductive biology. 2014 Apr;175:112-4.

Stone PR, Burgess W, McIntyre JP, Gunn AJ, Lear CA, Bennet L, et al. Effect of maternal position on fetal behavioural state and heart rate variability in healthy late gestation pregnancy. The Journal of Physiology. 2017 Feb 15;595(4):1213-21.

Murray I, Hassall J. 2014. Change and adaptation in pregnancy. In: Marshall J, Raynor M. eds. Myles Textbook for Midwives. 16th ed. Edinburgh: Churchill Livingstone, 143-177

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Read about the Sleep On Side campaign

Last reviewed on November 20th, 2017. Next review date November 20th, 2020.

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  • By Stevie (not verified) on 20 Oct 2018 - 20:43

    I’m worried that laying on my side is gonna hurt my baby, like what if I squash his head with my weight or something?

  • By Midwife @Tommys on 23 Oct 2018 - 12:36

    If you are overweight it is all the more important to sleep on your side rather than on your back. Your baby is protected inside a fluid filled uterus and is unlikely to be squashed. Make sure that you exercise as much as you can and try to eat a healthy diet with at least 5 vegetables and fruit each day.

  • By chomba Judith (not verified) on 30 Jun 2018 - 00:57

    I always try to sleep on my side but some times when I woke up I find myself on my back. 8 months

  • By Midwife @Tommys on 2 Jul 2018 - 09:49

    Hi Chomba, Try not to worry about this. Just turn over onto your side again and go back to sleep. Take care

  • By Jennifer (not verified) on 20 Jun 2018 - 15:58

    How does this advice sit with the guidance from the NHS?

  • By Midwife @Tommys on 21 Jun 2018 - 16:58

    Hi Jennifer,
    The advice is the same as the NHS which is to avoid going to sleep on your back in the third trimester.
    Best wishes
    Tommy's midwife

  • By Lora (not verified) on 23 May 2018 - 02:41

    No matter what side I lay on I get really bad Indigestion Some nights I wake up with rib pain. Laying on my left side gives me lower back pain. 38+6

  • By Midwife @Tommys on 24 May 2018 - 11:32

    Hi Lora, Thank you for your comment.
    As you are now 38+6 and this pain is waking you up at night we would recommend that you call your local maternity unit so that you can have an antenatal check. Have your blood pressure checked and get a midwife to test your urine for protein. The reason for this is that pre-eclampsia can cause upper rib pain which is similar to indigestion. Please don't be alarmed as this could just be indigestion, however, as you are at the end of your pregnancy then it is important that you get this checked out. Hope this helps, take care, Tommy's Midwives x

  • By Anniesa (not verified) on 15 Mar 2018 - 14:29

    Even on my side I have shortness of breath what can help

  • By Midwife @Tommys on 15 Mar 2018 - 16:47

    I am unsure if you are experiencing this when just on your side or your shortness of breath is continuous. If this is on going then do speak with your midwife, as this can be a sign of low iron levels or rarely, something more serious. Best wishes, Tommy's midwives.

  • By Jass (not verified) on 12 Mar 2018 - 22:44

    Hi I’m 29 weeks pregnant
    Can I sleep on my right side . Is it safe

  • By Midwife @Tommys on 15 Mar 2018 - 12:08

    Hi, Thank you for you comment.

    It is safe to sleep on either your right of left side, as long as you fall asleep on your side then this is beneficial for you baby. Hope this helps, Take Care, Tommy's Midwives x

  • By Lola (not verified) on 20 Nov 2017 - 16:14

    As a physio I have treated many women with pelvic arthropathy and have often given advice regarding lying on side which has been to position pillows in an L shaped position at the front of the pelvis. This means that the uppermost leg should rest on the pillows giving support to the sacroiliac joint which is the cause of a lot of pain in pregnancy due to lax ligaments. When advising people to lie on their side it may be helpful to give advice on how to do it safely and with comfort which might aid compliance.

  • By Midwife @Tommys on 22 Nov 2017 - 09:17

    Hi Lola! That is brilliant feedback and very useful to our women- so thank you!

  • By Lisa (not verified) on 20 Nov 2017 - 16:08

    I'm 8 months pregnant and finding it difficult to sleep for the whole night on my sides. I have tried being on my back but propped up with some pillows and slept really well. Is this safe? How propped up do I need to be?

  • By Midwife @Tommys on 22 Nov 2017 - 09:16

    Hi Lisa.
    Congratulations on your pregnancy! I know it can be ever so tough in the third trimester to get comfortable in bed. It sounds as if you are changing positions - from side to side and more upright and this is perfectly safe. You will need to be fairly upright when propped up with pillows to ensure that you do not slip down into a flat - back position. Most women feel quite dizzy or breathless if they try to lay too flat on their back regardless, so try not to worry. Your frequent position changes (and likely trips to the loo) will ensure that you are unlikely to be in one position for too long anyway! Take care and please contact us again if you have any further questions.

  • By Nanette (not verified) on 20 Nov 2017 - 13:09

    Hi, I've been tending to lie on both sides as depending on what position each twin is in I can be more comfortable on right than left or vice versa.
    Is there any advice on twin pregnancies please? should I still aim for left side (mine have their own placentas, twin 1 head down, twin 2 moves & changes position regularly). Thank you

  • By Midwife @Tommys on 22 Nov 2017 - 09:11

    Hi Nanette.
    Congratulations on your twinnies! No, there should not be any difference between a single or twin pregnancy(although this was not a part of the research trials i must admit) . Laying on your side, left or right, means that the blood flow and oxygen is optimal to both babies. Keep up the awesome side sleeping mummy! And feel free to contact us again if you need more advice!

  • By Caroline (not verified) on 20 Nov 2017 - 11:53

    Presumably this advice applies to laying on our backs generally, and not just when sleeing? Bit of a ‘first world problem’ but for example things like beauty treatments (i’ve been lucky enough to have been bought some as a pre-baby pamper!) can mean you may be on your back for 1-2 hrs at a time. Would you recommend not doing this at all? Or is it safe olif we sit up every so often? And if so how often? Some more advice would be really appreciated as i’ve got in a bit of a oanic over it all and may end up cancleling everyhing at this rate! Thank you x

  • By Midwife @Tommys on 20 Nov 2017 - 11:57

    Hi Caroline. You can certainly go for your facial, but simply ask the beautician to sit you up on the massage bed/treatment bed. You do not need to be laying flat to have a facial or to enjoy having a facial. But yes, do not lay flat on your back for this treatment.

  • By Lola (not verified) on 20 Nov 2017 - 06:42

    As a physio I have treated many women with pelvic arthropathy and have often given advice regarding lying on side which has been to position pillows in an L shaped position at the front of the pelvis. This means that the uppermost leg should rest on the pillows giving support to the sacroiliac joint which is the cause of a lot of pain in pregnancy due to lax ligaments. When advising people to lie on their side it may be helpful to give advice on how to do it safely and with comfort which might aid compliance.

  • By Midwife @Tommys on 20 Nov 2017 - 10:20

    Many thanks for your feedback Lola! We do discuss the use of pillows too, to ensure that women are both safe and comfortable when settling down to sleep!
    On social media tomorrow, as part of the campaign, we are discussing practical tips on sleeping, focusing on the use of pillows and supports.

  • By Anonymous (not verified) on 13 Sep 2017 - 21:04

    **Tip** Im a natural back sleeper so tried lots of things during my 2 pregnancies, i found that tying my hair into a low bun almost always stopped me from rolling onto my back.

  • By Midwife @Tommys on 14 Sep 2017 - 14:59

    Hi, Thank you for sharing your helpful hint, different things can work of every women so it is great to hear about what worked for you in your pregnancy. Tommy's Midwives x

  • By Keely (not verified) on 12 Oct 2017 - 03:57

    I totally agree with this. I hate to lay on a bun!! Great tip!

  • By Midwife @Tommys on 12 Oct 2017 - 10:35

    Hi, Thank you for your comment.
    There are lots of helpful aids that can encourage safer sleep but if you start on your side before you go to sleep then this would be great position to start in sleeping pregnant women, avoid sleeping on the back during pregnancy. Hope this helps, best wishes. Take Care Tommy's Midwives x

  • By Em (not verified) on 15 Aug 2017 - 14:54

    I have severe SPD and can barely move. In constant pain. I cannot lay on my sides! It is too painful and no amount of maternity pillows make a difference. I sleep almost upright just so I can get some sleep! This has really worried me!! What else can I do??

  • By Midwife @Tommys on 15 Aug 2017 - 16:42

    We're sorry to hear about your SPD and hope you are getting support in managing it.
    We don’t want you to become anxious. If your pregnancy is uncomplicated your risk of stillbirth is low even if you go to sleep on your back. Going to sleep on your side will make it even lower.
    It can be very difficult to find comfortable or even less painful position to sleep in if you have SPD. We're assuming from your message that you have tried placing a pillow between your legs and under your bump to assist side sleeping.
    The advice above is to avoid going to sleep on your back as the position you go to sleep in is the one you hold for longest during the night. Going to sleep propped up avoids the supine position, which is fine. We don’t have evidence that propped up carries a stillbirth risk therefore it’s very unlikely that you’ll be affected.
    If you are worried please speak to your midwife/physiotherapist and ask for suggestions on safer sleeping with SPD.

  • By Sheila robb (not verified) on 16 Jun 2017 - 08:51

    There are other reasons not just this.

  • By Midwife @Tommys on 16 Jun 2017 - 16:03

    Hi, absolutely there are other reasons however this is new research and evidence coming out which we try to let all women know about which can help to lower risk of stillbirth.

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