Sleeping Position Sayings

Pregnancy.org champions "SOS" (sleep on side), particularly the left side, for pregnant women, claiming this "will increase the amount of blood and nutrients that reach the placenta and your baby."
It is recommended that people at risk of obstructive sleep apnea sleep on their side and with a 30° or higher elevation of the upper body. Snoring, which may be (but is not necessarily) an indicator of obstructive sleep apnea, may also be alleviated by sleeping on one's side.