The most dangerous drug in the world: 'Devil's Breath' chemical from Colombia can block free will, wipe memory and even kill. 1  Scopolamine often blown into faces of victims or added to drinks.
To summarize, it appears the best position is left side, followed by right side. After 16 weeks it's best not to sleep on your back, and you probably won't sleep on your stomach. (One way to avoid sleeping on your back is to sew a tennis ball into the back of your pajamas; this works for people who snore, too).
During pregnancy you may find yourself wrestling in bed trying to get comfortable before falling asleep. Unfortunately, your regular sleeping positions may no longer work for you during pregnancy. There are a number of reasons for this new discomfort, but there are some sleeping positions that you can try that may help you get your much needed rest.