During the first trimester of pregnancy, it is generally considered safe to sleep on your stomach. However, as your belly grows and your uterus expands, it may become uncomfortable or even impossible to continue sleeping in this position. It is recommended that you start transitioning to sleeping on your side by the second trimester. Sleeping on your left side is particularly beneficial as it improves blood flow and nutrient delivery to both you and your baby. If you find it difficult to adjust, try using pillows for support or investing in a pregnancy pillow designed specifically for expectant mothers. Remember, always consult with your healthcare provider for personalized advice based on your specific circumstances.