Final answer:
Stage One of labor, also known as the cervical dilation stage, is the phase where the cervix thins and dilates to 10 cm, facilitated by true labor contractions. This stage is essential for the baby's eventual passage during birth and can last 6-12 hours, with the frequency and strength of contractions increasing over time.
Step-by-step explanation:
The stage of labor that begins with the onset of true labor contractions and ends with the complete dilation and effacement of the cervix is known as Stage One, or the cervical dilation stage. During this phase, the cervix must dilate fully to 10 cm in diameter to allow for the delivery of the newborn's head. The dilation of the cervix is critical for the baby and placenta to be expelled during birth. This stage is the longest and can vary greatly in duration but typically takes 6-12 hours. As true labor progresses, uterine contractions become more frequent and powerful, helping to further efface and dilate the cervix.
If labor should stall before reaching Stage Two, where the baby is expelled from the uterus, synthetic oxytocin, known as Pitocin, can be administered to restart and maintain contractions.