This was something I was always curious about as a mother and a new student. How can providers really tell? Isn't it very subjective? Is 7 cm dilated for one L & D nurse the same thing as 7 cm for the doctor? How is it that every woman and every baby just needs to make it to 10 cm? Won't larger women or women with larger babies have to dilate more? The fact is that it is very subjective. And you could be 10 cm (if it were possible to use a measuring tape on your cervix) and still have more to dilate. That is why the more appropriate term is "complete." You dilate centimeter by centimeter, cervix softening and opening around baby's head until it is no longer in front and no longer reachable by your provider. However, keep in mind you can not put numbers on babies in natural birth. A mother could be zero centimeters and deliver a baby that evening and another woman could walk around town at five centimeters for weeks. Also note that just because a woman is complete doesn't necessarily mean that it is time for her to push. Most deliveries go much more smoothly with a less exhausted mother when she is allowed to "labor down" and wait until the urge to push is strong. That being said, below is a visual representation of what in diameter will be similar to your cervix when you are in labor.
