Try your hardest to sleep on your left side. Because not only is that the best position for blood flow, your stomach is also lower than your esophagus so it helps prevent heart burn. I am 30 weeks and sometimes wake up on my back. It's fine if you catch it early.
Try your best to lay on your left side i start that way but always end up on my back this is my 5th baby and its never done any harm to mine.
Its your left side your ment to lie on not right...
NO!! Try sleeping on your right side. You don't want to sleep on your back or your left side for long periods of time. I'm 24W2D, my husband is an EMT and those 2 positions are the worse for you and the baby. It cuts off your main blood supply to the baby. Right side with a pillow between your legs is the best!