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).
By three months, most babies can sleep for about six hours a night and are more alert during the day. If your baby isn't napping regularly, you should start working on a sleep schedule. Sleep experts and parents agree that the key to successful napping is to be consistent: Baby naps at the same time, in the same place, with the same routine each day.