Once it becomes uncomfortable to be on your back. Your body will tell you these things. Everyone is different tho and what's ok or works for some isn't the case with others.
What about laying on your stomach? Im constantly trying to fall asleep on my sides but I always end up on my stomach. Im 5 months prego and not showing yet. My baby is sitting very low idk if that means anything...
Depends. I'm 36 weeks and can still lay on my back without being uncomfortable or harming my baby.
My hips always start hurting at night, I'm always flipping sides, I think it's because I'm in my 30's now lol. I've woken up on my back a number of times. I don't like to put pillows behind my back cuz I can't stay on one hip too long. My doc said not to worry because your body will wake you up if it's getting to long. But I sure would like some tips on the acing hips.
Once baby gets larger, into the early-mid trimester you should switch to your sides. Try putting pillows under your back to help keep you elevated off your back.