Yes sleeping on your right side during pregnancy is considered safe, especially in the first and second trimesters.
You’ve probably heard the pregnancy sleep rule from every direction: sleep on your left side. It’s repeated by doctors, doulas, and pregnancy apps so often that lying on your right side can feel like a mistake. But is right-side sleeping actually off limits during pregnancy, or is it a safe alternative?
The short answer is yes — right-side sleeping is generally safe during pregnancy, especially in the first and second trimesters. In the third trimester, side sleeping overall is recommended, and the left side is considered ideal for blood flow. However, right side is a perfectly acceptable alternative and far preferable to lying on your back. This article explains the research and helps you decide.
Why Side Sleeping Matters in the Third Trimester
Starting around 28 weeks of pregnancy, most health organizations recommend side sleeping. The advice is rooted in anatomy: your growing uterus can compress the inferior vena cava, a large vein that runs along the right side of your spine and returns blood to your heart. The left side is often highlighted because it gives that vein the most room to work, allowing for maximum blood flow to the placenta and fetus.
But the right side is not off limits. Research suggests that either side is fine for most pregnant people. The key is to avoid sleeping flat on your back, which can reduce cardiac output and lower blood return to the heart. Side sleeping — on either side — improves circulation and helps keep blood flow to your baby steady.
It is also completely normal to change position during sleep. Many pregnant women wake up on their back or right side despite falling asleep on the left. That movement is natural and not a cause for alarm.
Why Left Side Gets the Spotlight
Left-side sleeping is often called the “gold standard” because of a few anatomical advantages. Understanding those benefits helps explain why the left side is recommended — and why the right side is still a safe backup.
- Better vena cava clearance: The inferior vena cava runs on the right side of the spine. Sleeping on the left keeps the uterus off this major vein, allowing blood to flow back to the heart without obstruction.
- Improved kidney function: Left-side positioning can help your kidneys filter waste more efficiently, reducing swelling in your hands and feet.
- Optimal space for your liver: Lying on the left gives your liver room to function without pressure from the growing uterus.
- Higher cardiac output: Studies in awake pregnant women show that the supine (back) position lowers cardiac output compared to the left lateral position. Left-side sleeping maintains stronger circulation.
While these benefits are real, experts emphasize that the right side is still a safe choice. The left side is ideal, but the right side is a perfectly reasonable alternative — especially if you find it more comfortable or if you shift positions during the night.
What the Research Says About Right-Side Sleeping
The evidence on right-side sleeping is not as clear-cut as the left-side advice. Some older studies have linked back sleeping and right-side sleeping with a higher risk of stillbirth, reduced fetal growth, and low birth weight. However, that research is not definitive for right-side sleeping alone. A 2019 NIH science update notes that the evidence is mixed and that more study is needed to separate the risk of back sleeping from the risk of right-side sleeping.
On the other hand, some clinicians argue that the left-side advice may not apply to everyone. A 2016 article in the Journal of Obstetrics and Gynaecology Canada suggests that some women naturally shift positions due to pre-syncopal (faintness) episodes, and that side sleeping overall — on either side — is what matters most. The strongest consensus across top sources is that side sleeping is safer than back sleeping in the third trimester, and the right side is a safe alternative.
For a closer look at the study data, the NICHD has a detailed summary on right-side sleeping and stillbirth risk. Their review concludes that the evidence is not strong enough to recommend avoiding the right side entirely, and that the main goal is to avoid back sleeping.
| Sleep Position | Benefits | Risk Level (Third Trimester) |
|---|---|---|
| Left side | Maximizes blood flow to baby; improves kidney function; keeps liver uncompressed | Lowest risk — most recommended |
| Right side | Still a side-sleeping position; far better than back; allows good circulation | Low risk — considered safe alternative |
| Back (supine) | None specific to pregnancy; may worsen reflux | Higher risk — avoid for extended periods, especially after 28 weeks |
| Left side with pillow support | Reduces hip and shoulder pressure; may ease heartburn | Lowest risk — recommended for comfort |
| Right side with pillow support | Same benefits as right side, with added comfort | Low risk — acceptable choice |
Your comfort matters. The best position is the one that lets you get decent rest while keeping you off your back as much as possible.
Tips for Comfortable Right-Side Sleeping
If you prefer or end up on your right side, a few simple adjustments can make it more comfortable and supportive for your changing body.
- Use a pregnancy or body pillow: Tuck a long pillow along your right side and hug it with your top arm. This keeps your spine aligned and takes pressure off your hips.
- Place a pillow between your knees: This helps prevent hip rotation and lower back strain, which can pull on the round ligaments.
- Try a wedge under your belly: A small wedge pillow can support your growing belly from the right side, taking tension off your abdominal muscles.
- Prop your upper body slightly: If you experience heartburn, a slight incline can help. Using a few extra pillows behind your head and shoulders while still lying on your right side may offer relief.
- Switch sides if you wake uncomfortable: It’s normal to move during sleep. If you wake on your right side and feel fine, you can stay put. If you’d like to change, gently roll to your left side — no need to stress over it.
Many women find that combining these tips with a supportive mattress makes a real difference. Listen to your body; if a position feels genuinely uncomfortable or painful, adjust.
How to Make Right-Side Sleeping More Comfortable
University of Utah Health notes that the right side is probably okay for pregnancy sleep, and the real focus should be avoiding the back. They also point out that propping yourself up with pillows can be a helpful option if side sleeping itself is uncomfortable. That means you have a few workable choices: side sleeping on the left, side sleeping on the right, or semi-reclined with support.
Anecdotal evidence from many pregnant women suggests that switching sides throughout the night is common and harmless. If you fall asleep on the left and wake on the right, you’re still sleeping on your side — which is the main goal. The body’s own mechanisms often shift position when blood flow dips, so you rarely stay in a problematic position for long.
For a straightforward look at why right-side sleeping is considered safe, the University of Utah Health explains it in this sleep on right side guide. Their main message: don’t panic about which side you’re on — just avoid lying flat on your back after the second trimester.
| Position | Third Trimester Recommendation |
|---|---|
| Left side | Ideal – best for blood flow |
| Right side | Safe alternative – acceptable |
| Back | Avoid – not for extended sleep |
The Bottom Line
Right-side sleeping is generally safe during pregnancy, especially in the first and second trimesters. In the third trimester, side sleeping on either side is far better than sleeping on your back. Left side is the preferred position for optimal blood flow, but right side is a suitable alternative and nothing to worry about if you find it more comfortable or if you shift during the night.
If you’re unsure about your sleep position in the third trimester, your obstetrician or midwife can give guidance based on your specific blood flow and placenta position.
References & Sources
- NICHD. “Pregnancy Sleep Position” Previous studies have linked back and right-side sleeping with a higher risk of stillbirth, reduced fetal growth, and low birth weight.
- University of Utah Health. “Im Pregnant Sleeping My Side Hurts” The right side is probably okay; the main goal is to avoid sleeping flat on your back.