Nighttime sleep is often affected as your belly grows, and many women wake up frequently which leaves them feeling tired. It is common to make more trips to the bathroom, and back and pelvis pain may cause you to change your sleeping position often. Sleeping on your side is usually the most comfortable. Use lots of pillows and make sure your bedroom isn’t too hot. If your nighttime sleep is very affected, try to take short naps to make up for lost sleep at night.
Source: - Lärobok för barnmorskor. Faxelid, E. Course literature 2001. - Myles Textbook for Midwives. Fraser, D. och Cooper, M. Churchill Livingstone 2003.