You have not mentioned how far pregnant you are. Before 20 weeks, you can sleep in any position. After 20 weeks, avoid sleeping flat on back as uterus can press on the large blood vessels. Side ways left or right is fine.

Enhances blood flow to uterus, placenta, and fetus Helps in better oxygen and nutrient supply to the baby It Improves Maternal Circulation Better blood return to the heart Reduces dizziness and supine hypotension So relatively it is better to sleep on left side but can take sides in between

No, it is not compulsory to sleep only on the left side during pregnancy. Left-side sleeping is preferred, especially in the later months, because it improves blood flow to the baby and reduces pressure on major blood vessels. Right-side sleeping is also safe and absolutely fine if that is more comfortable for you.

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It is not compulsory to sleep only on the left side. Left side sleeping is preferred in later pregnancy(term pregnancy) as it helps blood flow to the baby and reduces pressure on major blood vessels. However, sleeping on the right side is also safe and fine if that is more comfortable for you. But, avoid lying flat on your back for long in the last trimester.

You can change to right lateral too But left side is the preferred position.