There are three important words to be familiar with to help understand the labor process. They are dilatation, effacement, and station.
Dilatation is a measurement of how open the cervix is and is measured in centimeters. It ranges from 0 (closed) to 10 (completely dilated).
Effacement is how thin the cervix is and it is measured in percent. 0% effaced is a cervix prior to any change. 100% effaced is a completely thinned out cervix.
Station is a measure of how low the baby’s head is in the pelvis. It is measured from -3 to +4. A baby at -3 station is still very high in the pelvis and not close to delivery. If the baby’s head is at +4 station it is essentially delivered.
The doctors and nurses will talk about the progress of labor by using these three measurements in that order. For instance if the doctor says that you are 1/50/-2, that means your cervix is 1 centimeter dilated, half of the way thinned out, and the baby’s head is still rather high in your pelvis. In this situation you are either not in labor or in very early labor. If the doctor says you are 8/90/+1, that means your cervix is 8 centimeters dilated, mostly thinned out, and the head has come down significantly into the pelvis. In this situation you are close to delivery