In obstetrics, station refers to descent of the fetal presenting part (hopefully the head) in the pelvis.
An imaginary line is drawn between the two bones in the pelvis (known as ischial spines). This is the “zero” line, and when the baby reaches this line it is considered to be in “zero station.” When the baby is above this imaginary line it is in a minus station. When the baby is below, it is in a “plus” station. Stations are measured from -5 at the pelvic inlet to +4 at the pelvic outlet.
Cervical dilation and decent of the fetal head during labor should happen together, especially in a first labor. Sometimes descent doesn’t happen until later in the labor process with a second or third baby.
Station is an integral part of something known as the “Bishop’s Score.” The Bishop’s Score is a pre-labor scoring system that uses station as well as characteristics of the cervix including dilation, effacement, position and consistency to help in managing the labor induction process.