Pregnancy Tips

Best Position for Sleeping in Pregnancy

Dr. Kundan Ingale

August 06,2025

Pregnancy changes nearly every aspect of life including sleep. As the body grows and hormones shift, many women find it harder to sleep through the night. Among all the changes, one thing plays a surprisingly big role in restful sleep: your sleeping position. 

This guide walks you through the recommended sleeping positions throughout all three trimesters of pregnancy. You’ll also learn why certain positions matter, how to stay comfortable, and which sleep habits are safest for both mom and baby.

Why does sleep position matter during pregnancy?

As your baby grows, your internal organs begin to shift and compress. That means certain sleeping positions especially as the pregnancy progresses can affect blood flow, digestion, breathing, and even the baby’s oxygen supply.

Lying flat on your back after the second trimester can compress the inferior vena cava, a large vein that carries blood from your lower body back to your heart. This reduces circulation to the uterus and may make you feel dizzy or breathless.

Sleeping on your side particularly on the left side helps maintain healthy blood flow to the uterus, kidneys, and fetus. That’s why many healthcare professionals recommend side-sleeping as pregnancy advances.

Trimester-Wise Sleeping Positions

First Trimester (Weeks 1–13): Do What Feels Right

In the early weeks of pregnancy, your uterus is still small and well-protected by the pelvis. Most sleeping positions including on your back or stomach are considered safe.

Still, this is a good time to start building the habit of side-sleeping, especially on your left. Using a pillow behind your back or between your knees can make it easier to stay in position.

Tip: If you enjoy back-sleeping, try a wedge pillow under your right side. It slightly tilts your body while keeping pressure off your spine.

Second Trimester (Weeks 14–27): Time to Shift Sides

As your baby grows and your belly starts to show, side-sleeping becomes more important. The left side is preferred because it keeps the uterus from pressing on major blood vessels and helps kidneys flush waste more efficiently.

Sleeping on your right side is still acceptable, but the left is generally considered more beneficial for circulation.

To reduce pressure on your hips and lower back:

• Place a pillow between your knees.
  
• Use a small pillow under your belly for added support.
  
• Placing a cushion behind your back can help keep you from turning onto your back while you sleep
  

Third Trimester (Weeks 28–40+): Prioritize Comfort and Safety

By the third trimester, back-sleeping is strongly discouraged. A 2018 study suggests that consistently sleeping on your back after 28 weeks may slightly increase the risk of late stillbirth due to reduced blood flow.

At this stage, your body may naturally favor the side position. Your growing belly, leg cramps, and shortness of breath make back-sleeping uncomfortable.

To stay comfortable:

• Use a pregnancy pillow (U-shaped or C-shaped) to support your head, belly, hips, and legs.
  
• Keep your upper body slightly elevated if you struggle with heartburn.
  
• Stretch gently before bedtime to relax tense muscles.
  

Note: If you wake up on your back, don’t panic. Just return to your side. The key is to spend most of the night in a side position.

What Positions to Avoid?

Back-Sleeping (Especially After Week 28)

• Can lower blood pressure
  
• May cause dizziness or shortness of breath
  
• Reduces circulation to the baby
  

Stomach-Sleeping (After First Trimester)

• Becomes physically uncomfortable
  
• Puts pressure on the growing uterus
  

Tips to Improve Sleep During Pregnancy

• Stick to a consistent bedtime.
  
• Avoid caffeine in the afternoon and evening.
  
• Eat light, non-spicy meals before bed.
  
• Use extra pillows behind your back, under your belly, between your knees.
  
• Try gentle prenatal yoga or stretching.
  
• Keep your room cool, dark, and quiet.
  

The Science Behind Left-Side Sleeping

You might wonder: Why the left side?

The inferior vena cava is a large vein that runs slightly to the right of your spine. Sleeping on your back puts pressure on it, reducing blood flow to your heart, baby, and kidneys.

Sleeping on your left side helps:

• Improve circulation
  
• Enhance kidney function (reducing swelling)
  
• Helps ensure your baby receives an optimal supply of oxygen and nutrients.
  
• Reduce pressure on the liver
  

Final Thoughts

Sleeping on your side, especially the left, is considered the most beneficial position during pregnancy. It improves circulation, relieves common discomforts, and helps you and your baby rest better.

It’s okay if you shift positions at night just aim to start and return to your side. With a few pillow tricks and mindful habits, you can sleep comfortably and safely throughout your pregnancy.