Answer by
amswplusone (652)
When you're getting closer to delivery, your cervix dialates (opens up more) and thins to make way for the baby that's about to come through. When it's time for delivery you're usually dialated 10 centimeters and your cerivx is very thin. Being 80% effaced means your cervix has reduced it's thickness by 80% of the change you'd expect for delivery.