Hey Tinsel,
In my pregnancy yoga class they recommended squats for preparation for birth. We all leaned against a wall as if there is a seat right next to the wall, but supported ourselves with our leg muscles. It was easy at first then got harder when fatigue set in. The instructor said if we did this every day it will make our legs heaps stronger and less fatigued in labour, particularly if you want more range of birth positions to try.

Have fun!