A pregnancy pillow is the ideal solution for this. These pillows come in different shapes and sizes and are suitable for all stages of pregnancy. During the early weeks of pregnancy, your body will experience discomfort from your growing belly, making it important to sleep on your side. Your expanding uterus will compress your large blood vessels, reducing the blood flow to your placenta. This can cause pain in your ligaments and back, which can lead to fatigue and even faintness in the later months.