Sleeping on your back

If you have woken up on your back during pregnancy and immediately worried, the key advice is simple. After 28 weeks, the NHS recommends going to sleep on your side rather than your back. If you wake during the night and realise you are lying on your back, you do not need to panic. Turn onto your side before going back to sleep.

The guidance focuses on the position you go to sleep in, including when you return to sleep after waking and when you have a daytime nap. Either your left or right side is suitable.

Why is sleeping on your back discussed during pregnancy?

As pregnancy progresses, the uterus becomes heavier. In later pregnancy, lying flat on your back can place pressure on major blood vessels, which may affect blood flow to the baby.

Research has found an association between going to sleep on your back in the third trimester and an increased risk of stillbirth. This is why NHS England advises people who are more than 28 weeks pregnant to settle to sleep on their side.

The advice is about reducing risk. It does not mean that briefly finding yourself on your back has harmed your baby.

When should you stop going to sleep on your back?

Current NHS guidance recommends going to sleep on your side after 28 weeks of pregnancy.

This applies to:

going to sleep at bedtime
going back to sleep after waking during the night
daytime naps

Before 28 weeks, this specific safer-sleep recommendation does not apply in the same way.

If you have been given individual advice about sleep or positioning because of your health or pregnancy circumstances, follow the guidance from your maternity team.

What if you wake up on your back?

Waking on your back can feel frightening once you know about the guidance, especially if you have no idea how long you have been in that position.

The NHS specifically says not to worry if this happens. Simply turn onto your side before going back to sleep.

You cannot consciously control your position while you are asleep. The research and guidance therefore focus on the position you choose when settling to sleep.

If you wake several times during the night, you can use each waking as a reminder to settle back onto your side.

Does it matter which side you sleep on?

You can sleep on either your left or right side.

You may have heard that everyone should sleep specifically on their left side during pregnancy. Tommy’s notes that good evidence has not shown the left side to be safer than the right.

Comfort can therefore guide you. You might prefer one side, alternate between them during the night or find that your preference changes as your pregnancy progresses.

The important part of the NHS guidance after 28 weeks is going to sleep on your side rather than flat on your back.

What if you cannot get comfortable on your side?

Side sleeping can be difficult if you have spent most of your life sleeping on your back. Pregnancy itself can also make comfortable sleep harder, particularly if you are dealing with hip, pelvic or back discomfort.

Pillows may help. Tommy’s suggests trying a pillow beneath your bump and another between your legs. A pillow behind your back may also make it easier to remain supported on your side.

You do not need a particular pregnancy pillow. Ordinary pillows can work well, so experiment with what you already have before feeling that you need to buy anything.

If pelvic or back pain is making side sleeping particularly difficult, mention it to your midwife. They can discuss your symptoms and whether further support may be appropriate.

Do you need to stay on your side all night?

The guidance does not ask you to somehow prevent yourself from moving while asleep.

What matters is making side sleeping your starting position after 28 weeks. This includes settling onto your side again if you wake during the night.

Tommy’s explains that the position in which you go to sleep tends to be the position you spend the longest amount of time in during the night. That is why changing your going-to-sleep position is useful even though you may naturally move afterwards.

Trying to monitor every movement you make overnight is likely to make sleep more stressful without being realistic.

Does the advice apply to naps?

Yes. After 28 weeks, NHS England and Tommy’s advise going to sleep on your side for daytime naps as well as nighttime sleep.

The same principle applies if you wake from a nap on your back. Turn onto your side the next time you settle to sleep.

If you sometimes doze unexpectedly, do not use that as a reason to blame yourself. Focus on choosing a side position whenever you deliberately settle down to sleep.

What about lying on your back while you are awake?

The evidence behind the safer-sleep recommendation specifically concerns going to sleep on your back in later pregnancy.

That is different from briefly lying on your back while awake, such as while changing position or during an appointment.

If lying on your back makes you feel faint, dizzy, breathless or otherwise unwell, change position and seek advice if you are concerned. If a healthcare professional needs you in a particular position for an examination or procedure, they can advise you based on your circumstances.

Can you train yourself to sleep on your side?

If back sleeping has always been your preferred position, changing the habit may take a little time.

You could begin settling on your side before the 28-week point so the position feels more familiar by later pregnancy. Pillows behind your back, under your bump or between your knees can provide support.

If you wake on your back, treat it as a cue to turn over rather than evidence that you have failed to follow the guidance.

Sleep can already become fragmented during pregnancy. The aim is to make side sleeping your usual starting position, not to spend the night worrying about every movement.

When to get professional advice

Speak to your midwife if you are struggling to sleep on your side because of significant pain, discomfort or another health concern. They can give advice that takes your individual pregnancy into account.

Contact your maternity service promptly if you are worried about reduced fetal movements, vaginal bleeding, watery or unusual discharge, signs of pre-eclampsia or significant itching. NHS England advises pregnant people not to wait when these concerns occur.

If your baby’s movements are reduced, weaker than usual or have stopped once you normally feel movement, contact your maternity unit immediately rather than waiting until the next day.

For urgent medical advice when you are unsure what to do, contact NHS 111. Call 999 for a life-threatening emergency.