Can You Sleep on Your Back During Pregnancy?
After 28 weeks, side sleeping is recommended. Why position matters and how to stay comfortable.
In the first and second trimesters, sleeping on your back is safe. From about 28 weeks onward, sleeping on your side (preferably left) is recommended. Back sleeping in late pregnancy can compress the inferior vena cava, reducing blood flow to the uterus. If you wake up on your back, simply roll to your side — brief periods are not harmful.
😴 Why Back Sleeping Becomes a Concern
As your uterus grows, it becomes heavy enough to compress major blood vessels when you lie flat:
- Inferior vena cava compression: The uterus presses on this large vein, reducing blood return to the heart.
- Aortocaval compression: Can also compress the aorta, further reducing blood supply to the uterus.
- Reduced oxygen to baby: Decreased blood flow can lower oxygen delivery.
- Maternal symptoms: You may feel dizzy, short of breath, or nauseous — your body is signaling you to move.
A 2017 BMJ study found that back sleeping after 28 weeks was associated with a 2.6x increased risk of stillbirth. The absolute risk remains small, but side sleeping is a simple precaution.
✅ Recommended Sleep Positions
| Position | Status | Notes |
|---|---|---|
| Left side | Best | Optimal blood flow to placenta; helps kidneys |
| Right side | Good | Also safe; do not worry if you prefer this side |
| On your back | Avoid after 28 weeks | May compress vena cava; brief periods okay |
| On your stomach | Okay early on | Becomes impossible as belly grows |
| Semi-reclined (propped up) | Good alternative | Prop up at 30-45 degrees to reduce compression |
🛏️ Tips for Comfortable Side Sleeping
- Pregnancy pillow: A C-shaped or U-shaped pillow supports belly, back, and knees simultaneously.
- Pillow between knees: Reduces hip pain and keeps the spine aligned.
- Pillow under belly: Supports the weight of your growing belly.
- Pillow behind back: Prevents rolling onto your back during sleep.
- Elevate slightly: For heartburn, raise the head of your bed or use extra pillows.
- Alternate sides: Both left and right are safe. Switch when one becomes uncomfortable.
💡 Do Not Panic If You Wake Up on Your Back
- If you wake up on your back, simply roll to your side. Your body likely woke you because it detected the position change.
- Brief periods on your back are not harmful — the concern is about prolonged deep sleep in that position.
- Your body will usually alert you with dizziness or discomfort before any harm is done.
- If you can only fall asleep on your back, prop yourself up at 30-45 degrees with pillows.
- Sleep quality matters — a rested mother is healthier than an anxious one.
❓ FAQ
At what week should I stop sleeping on my back?
The general recommendation is to start sleeping on your side from about 28 weeks. Some guidelines suggest from 20 weeks. The key is to go to sleep on your side — do not worry if you occasionally shift during the night.
Is sleeping on the right side okay, or must it be the left?
Both sides are safe. The left side is often cited as slightly better for blood flow, but the right side is also perfectly fine. The main thing is to avoid sleeping flat on your back.
What if I can only fall asleep on my back?
Try propping yourself up at a 30-45 degree angle with pillows or a wedge. You can also place a pillow behind your back while on your side to create a slight backward lean.
Do I need to buy a pregnancy pillow?
A pregnancy pillow is not essential but can significantly improve comfort. You can also use regular pillows: one between knees, one under belly, and one behind your back.
Sources
- Stacey T. et al. — Sleep position and risk of late stillbirth (BMJ, 2017)
- NHS — Sleeping positions in pregnancy
- Tommy's — Sleep position in pregnancy research
- ACOG — Sleep during pregnancy