Best Sleeping Positions During Pregnancy

Best Sleeping Positions in Pregnancy: A Guide for Every Stage

Summary: In early pregnancy you can sleep in any position that is comfortable, including on your tummy or your back. As your bump grows in the second trimester, sleeping on your side becomes the most comfortable. From 28 weeks, go to sleep on your side, either left or right, and avoid going to sleep on your back, because studies found this roughly doubles the risk of stillbirth. If you wake up on your back, don’t worry; simply turn onto your side. Pillows between your knees, under your bump and behind your back make side sleeping easier.

Why does sleep position matter in pregnancy?

As pregnancy progresses, the womb grows larger and heavier. When you lie on your back in late pregnancy, the womb presses on the large blood vessels behind it, especially the vein that carries blood back to the heart (the inferior vena cava). This reduces blood flow to the heart, and then to the placenta and baby. Some women feel dizzy, sick or short of breath when lying on their back. Sleeping on your side takes this weight off these blood vessels.

First trimester (up to week 13)

Early pregnancy: any comfortable position is fine: side, back or tummy.

At this stage the womb is still small and protected inside the pelvic bones, so you can sleep in whatever position feels best, including on your tummy or your back. This does not harm the baby.

What matters most now is getting enough sleep, because tiredness is very common due to the hormone progesterone. It is also a good time to get used to sleeping on your side, as this will become the best position later.

Second trimester (weeks 14 to 27)

Second trimester of pregnancy (from week 14 to 27)

Second trimester: lying on your side with a pillow between your knees is the most comfortable.

·       On your tummy: this becomes uncomfortable as the bump grows, usually between weeks 16 and 20. It does not harm the baby, but most women stop naturally.

·       On your back: still allowed, but some women feel dizzy or short of breath when lying flat on their back. If this happens, turn onto your side.

·       On your side: the most comfortable position at this stage. A pillow between your knees eases pressure on your back and hips.

Third trimester (week 28 until birth)

From 28 weeks: sleep on your side with a pillow between your knees, a small pillow under your bump and another behind your back.

This is the most important stage. From 28 weeks, always go to sleep on your side: at night, when you go back to sleep after waking, and for daytime naps.

Large studies found that going to sleep on your back in the third trimester roughly doubles the risk of stillbirth compared with sleeping on your side. The actual risk is still low, but it is a risk you can avoid with one simple step.

From 28 weeks: avoid going to sleep on your back.

Left side or right side?

Both the left and the right side are safe. Choose whichever is comfortable for you.

In the past women were told to sleep on their left side specifically, but recent studies found no difference in the baby’s safety between the two sides. So sleep on whichever side is comfortable, and feel free to switch sides during the night.

Woke up on your back? Don’t worry

It is normal to move during sleep. The position you fall asleep in is the one you stay in the longest, so what matters is to start your sleep on your side. If you wake up on your back, simply turn onto your side and go back to sleep.

Pillow tips for comfortable sleep

·       A pillow between your knees: supports your back and hips and keeps your pelvis level.

·       A small pillow under your bump: carries its weight and eases strain on your back.

·       A pillow behind your back: stops you rolling onto your back while asleep.

·       A long pregnancy pillow (C- or U-shaped): does all of this in one pillow.

·       For heartburn or breathlessness: raise your head and chest with an extra pillow while staying on your side, and avoid heavy meals for at least two hours before bed.

When to contact your doctor straight away

·       If you feel your baby is moving less, or the pattern of movements has changed: do not go to sleep; call your doctor or go to the hospital the same day.

·       Severe dizziness or fainting.

·       Severe breathlessness, or a severe headache with swelling of the face and hands.

Frequently asked questions

Does sleeping on my tummy in early pregnancy harm the baby?

No. In the first months the baby is protected inside the pelvis, and you can sleep on your tummy as long as it is comfortable.

Is lying on my back for a short time after 28 weeks dangerous?

Lying on your back briefly while awake, for example during a check-up or a few minutes’ rest, is not a problem. The advice is about going to sleep on your back for long periods. If you feel dizzy, turn onto your side.

Does this advice apply to daytime naps?

Yes. From 28 weeks, go to sleep on your side every time, day or night.

For more on sleep difficulties and how to improve them, read our article on sleeping problems during pregnancy.

Dr. Najeeb Layyous F.R.C.O.G

Consultant in Obstetrics, Gynaecology and Infertility