A 31 y/o G3P2 presents to L&D. She reports that her "water broke" 3 hours ago. Is she in labor?
A. Yes
B. No
C. Maybe so

Labor is defined as regular uterine contractions resulting in cervical change.
Questions we have for mom:
Contractions?
Questions we need to find out:
Cervical change?

Note that rupture of membranes is NOT in the definition of labor (contrary to pop culture belief.
You find out she is having regular contractions every 2-3 minutes. On exam, she is 5cm dilated, 50% effaced, and -1 station.

What does that mean?
Dilation: opening of the cervix; measured in cm wide
Effacement: thinning, or "shortening", of the cervix; measured in percentages (100% being the most thin)
Station: relation of the fetal presenting part to the ischial spine (point 0); negative being above the ischial spine, positive being below

Answer:
C. Maybe so