It is generally recommended for pregnant women to avoid sleeping on their back or stomach, especially during the later stages of pregnancy. Sleeping on your back can put pressure on major blood vessels and restrict blood flow to the uterus and baby. This can lead to dizziness, shortness of breath, and decreased oxygen supply to the baby. However, sleeping in a straight position on your side is considered safe and beneficial for both you and your baby. The best sleeping position during pregnancy is usually the left side as it improves blood circulation and helps with digestion. If you find it uncomfortable to sleep in a straight position, you can use pillows or maternity support cushions to provide extra comfort and support. It's important to prioritize your comfort while also ensuring the safety of your baby during sleep. If you have any concerns or specific medical conditions, it's always best to consult with your healthcare provider for personalized advice.