From 28 weeks, aim to go to sleep on either your left or right side for nighttime sleep and naps. If you wake on your back, do not panic—simply roll onto a side and settle again. Current guidance focuses on the position in which you fall asleep, not on controlling every movement you make overnight. NSW Health’s late-pregnancy sleep-position guidance advises side-settling for all sleep episodes from 28 weeks.
A pregnancy pillow can make side sleeping more comfortable, particularly as your bump grows. It is a comfort aid, though—not a device that can guarantee you will remain on your side or prevent pregnancy complications.
From 28 Weeks, Start Sleep on Either Side
The practical plan is simple:
- Settle on the side that feels comfortable at bedtime and before a daytime nap. Left and right side sleeping are both considered acceptable in late pregnancy unless your own maternity clinician has given you different advice.
- After a nighttime waking, resettle on a side when you return to sleep.
- If you wake up flat on your back, roll over without alarm. Waking in that position does not mean you have done something wrong or that you need to stay awake worrying about it.
There is no need to treat the left side as the only acceptable option. The useful habit is beginning each sleep episode on a side, then returning to a side when you notice you are on your back.
Bodies move during sleep. The goal is a realistic routine, not perfect position control all night.
Why Flat Back Sleeping is Discouraged in Late Pregnancy
The recommendation comes from observational research linking going to sleep on the back in late pregnancy with a higher likelihood of stillbirth than going to sleep on a side. This research identifies sleep-onset position as a potentially modifiable factor, but it does not prove that lying on the back directly causes harm in every situation.
One proposed explanation is that, later in pregnancy, lying flat can allow the uterus to put pressure on major blood vessels. This may reduce blood flow back to the heart and can affect circulation to the uterus and placenta. It is also why some people feel uncomfortable, lightheaded, or short of breath when lying flat.
The important distinction is this:
- The evidence and guidance concern falling asleep on the back in late pregnancy.
- They do not mean you must monitor your position constantly while asleep.
- They do not directly establish the risk of a brief period on your back while awake.
For example, the available guidance does not equate falling asleep supine with a short, awake interval while having an ultrasound, changing position in bed, getting up, or following a clinician’s instructions during an examination. If an appointment, exercise, reflux symptom, pain issue, or medical condition makes a position difficult, ask your midwife or maternity clinician what is appropriate for you.
Make Side Sleeping More Comfortable with a Pregnancy Pillow
Pregnant adult arranging supportive pillows for a comfortable side-sleep position
A pillow setup can make it easier to begin sleep on your side—especially if hip, pelvic, back, or bump discomfort keeps interrupting your rest. Choose a shape and arrangement based on what feels supportive, not on a promise that it will stop you rolling over.
Between Your Legs
Place a pillow between your knees and lower legs while side lying. Keeping the upper leg from resting directly on the lower leg may be more comfortable for people experiencing pelvic girdle pain.
A smaller pillow can work well here, or one section of a longer pregnancy pillow can be positioned between the legs.
Along the Front of Your Body
The approved evidence does not describe specific front-of-body pillow positioning. For comfort, consult your maternity clinician.
Behind Your Back
One or two pillows placed behind your back may make side lying feel more secure and comfortable. This can be useful if you prefer a little support at your back while settling down.
Think of this as a comfort cue rather than a barrier. A pillow behind you cannot guarantee that you will not roll during sleep, and it should not be treated as protection against stillbirth or other complications. Side-sleeping guidance for late pregnancy similarly emphasizes returning to a side if you wake on your back, while noting that sleep movement is not fully under conscious control.
If you have severe pain or a medical condition that prevents side sleeping, evidence suggests using at least a 30-degree head-end tilt rather than lying flat. Consult your maternity team for individualized advice.
When to Contact Your Midwife or Maternity Unit
Change position if lying flat makes you feel unwell. Contact your midwife, obstetric clinician, or maternity unit for advice if symptoms when lying back are persistent or keep returning, including:
- Dizziness or feeling faint
- Severe pain or a condition that prevents comfortable side sleeping
Treat reduced or changed fetal movement as a separate reason to contact your maternity team promptly, using the urgent pathway you have been given locally. Do not wait for a particular time of day or try to solve a movement concern by changing pillows or sleep position.
Tonight’s Late-Pregnancy Sleep Plan
- Begin your night and naps on the side that feels most comfortable.
- Use a pillow between your legs or behind your back if it helps you relax.
- If you wake on your back, calmly roll onto either side and go back to sleep.
- Contact your maternity team for concerning symptoms, difficulty finding a tolerable position, or any change in fetal movement.
