As the pregnancy progresses, it is generally recommended to avoid laying on your stomach. Around 17 weeks or when the belly starts to grow, it can become uncomfortable and potentially harmful for both the mother and baby. Laying on your back after 20 weeks can also cause issues due to pressure on major blood vessels. Instead, try sleeping on your side with a pillow between your legs for support. This position promotes better blood circulation and reduces strain on your back. Additionally, using a pregnancy pillow or wedge can provide extra comfort and support while sleeping. Remember to consult with your healthcare provider for personalized advice based on your specific situation.