OK, in layman's terms, here is how my doc described it. Your birth canal is like a hallway leading to your vagina, which is like a doorway. When the birth canal starts to soften and give way and shorten, it is called "effacing". When the vagina starts to open, it is called "dilating". The birth canal can efface all the way before you are fully dilated. Generally, when one is 100% effaced, they are beginning to dilate a little bit at least, but it also happens quite often that a person will not dilate at all until after they are fully effaced. Hope I helped!
at 3:24 PM on Jun. 3, 2010