Sleep Positions in Pregnancy: Must You Stay on Your Left All Night?

You are sleepy but still cannot find a comfortable position. Your left side starts to ache. Yet you hesitate to turn right because you have heard that pregnant women must sleep on their left.

You can lie on your right side. Sleeping during pregnancy does not mean staying on your left all night. From 28 weeks of pregnancy, the NHS recommends going to sleep on your side, either left or right, rather than on your back. So if one side begins to ache, you can change sides. ¹

Why is side sleeping recommended during pregnancy?

As your bump grows, lying on your back can cause the uterus to press on major blood vessels. This pressure can make you feel dizzy and reduce blood flow to the fetus. ²

ACOG, the organization of obstetricians and gynecologists, also describes side sleeping as a better choice during the second and third trimesters. You can therefore begin getting used to it before 28 weeks of pregnancy. ²

However, advice to sleep on your side does not mean enduring soreness just to stay on your left. Either side is fine unless the doctor or midwife caring for your pregnancy gives specific instructions. ¹

What if you wake up on your back?

You wake during the night and realize you are on your back, even though you went to sleep on your side.

There is no need to panic. Simply turn onto your side again when going back to sleep. ³

We cannot continually control our body position while asleep. Tommy’s guidance explains that research on this subject assesses the position in which you fall asleep, rather than requiring you to maintain one position until morning. ³

Make a habit of choosing a side-lying position whenever you go to sleep. This applies at night, during naps, and when returning to sleep after getting up to use the bathroom. ³

On your side but still uncomfortable? Try adjusting your pillows

You are on your side but keep shifting to feel comfortable. Before adding pillows, look at where the pillows you already use are placed.

As well as under your head, a pillow can be placed between your knees and beneath your bump. Both are approaches ACOG recommends to help pregnant women lie more comfortably. ²

Try a pillow between your knees

While lying on your side, bend your knees slightly and place a pillow between them. Let your legs rest comfortably; there is no need to squeeze the pillow tightly. ²

Lie still for a moment before adjusting again. Does it feel better now, or do you still need to move your legs to get comfortable?

Add a pillow under your bump if needed

A growing bump may also feel more comfortable with a pillow beneath it. Try a pillow you already have, moving it a little at a time until it feels right. ⁴

Make one adjustment first and notice the difference. Adding several pillows at once makes it harder to tell which one is helping.

For your head pillow, do not judge height from photographs alone. Lie on it and notice how thick it is once compressed by your head. You can read the guide to choosing a pillow for your sleep habits to compare options.

Do you need a special pregnancy pillow?

Not necessarily. Ordinary pillows can work too. Tommy’s notes that some women find pregnancy pillows helpful, while others use a few ordinary pillows. ⁴

However, if you need to arrange several small pillows every night, a pregnancy or maternity pillow can be an option. Compare its shape with the pillow positions that have felt comfortable for you.

Before buying, picture its position on your mattress too. Once the pillow is in place, is there enough room to turn over, particularly if you share the bed?

C-shape or U-shape?

Premium Maternity Body Pillow MojoDream comes in C and U shapes. Both measure 70 × 150 cm, weighing approximately 4 kg for the C-shape and 5 kg for the U-shape. ⁷

The dimensions are the same, but the shapes differ. When looking at the product photographs, consider these two points:

Consider its weight too if you will often lift or move it yourself. Do not leave this until after the pillow arrives.

Comfortable lying down, but still struggling to sleep?

Sometimes you find a comfortable position only to wake again needing the bathroom. A growing bump and needing to urinate more often can disrupt sleep during pregnancy. ¹

If heartburn is what bothers you, look at your meal timing. The NHS recommends smaller meals and leaving three hours between your last meal and bedtime. ⁵

For heartburn, raising your head and shoulders and lying on your left side may also help. The left side may feel more comfortable with these symptoms, but that does not mean the right side is always wrong. ^{1, 5}

If pain makes movement difficult, get it checked

Pelvic pain making it difficult to turn in bed, walk, or climb stairs? Tell your obstetrician or midwife. Symptoms like these may need assessment and physiotherapy, not just another pillow. ⁶

The same applies if lack of sleep makes daily activities difficult or affects your emotional well-being. Discuss your symptoms, and do not try sleeping medicines or herbal remedies without consulting first. ⁴

Tonight, try adjusting your pillows while lying on your side. Use what you already have and notice whether the position feels more comfortable. If soreness or trouble sleeping continues to bother you, raise it during a consultation; not everything can be resolved by changing pillows.

This article provides general information and does not replace advice from the doctor or midwife caring for your pregnancy.

Sources and further reading

1. NHS — Tiredness and sleep problems in pregnancy.
2. ACOG — Can I sleep on my back when I’m pregnant?.
3. Tommy’s — Sleep on your side.
4. Tommy’s — How can I get more sleep in pregnancy?.
5. NHS — Indigestion and heartburn in pregnancy.
6. NHS — Pelvic pain in pregnancy.
7. Mojokoe — Premium Maternity Body Pillow specifications.