And what happens is it begins to relax, it dilates and it flattens out. And this is important because that is essentially what allows the head of that fetus to make its way into the tract of the vagina. Now, eventually, towards the end of stage one, we have the amnion that ruptures. So the AMN is that sac, the fluid filled sac that contains that developing embryo and that developing fetus. And so what happens towards the end is it ruptures, releasing about one liter of amniotic fluid through the vaginal cavity and into the outside environment. And so this is when that woman knows she's at the end of stage one.