Final answer:
The first stage of labor, which is the longest, includes three phases: early cervical dilation, active labor, and transition. The cervix must dilate to about 10 cm to allow for the birth of the baby. The duration of this stage can vary, with prior births usually resulting in a shorter dilation phase.
Step-by-step explanation:
The first stage of labor is the longest part of the childbirth process and involves three main phases: early cervical dilation, active labor, and the transition phase. During early cervical dilation, the cervix thins and begins to open, which is necessary for the baby and placenta to eventually pass through. This stage can last 6-12 hours or more, especially for first-time mothers, and the cervix will dilate up to about 10 cm. The active labor phase follows, characterized by stronger, more frequent contractions leading to further dilation of the cervix. Lastly, during the transition phase, the dilation is completed, and the body prepares to enter the second stage of labor, wherein the baby will be expelled.
Prior births can influence the length of labor, as the dilation stage tends to be shorter in subsequent labors. If labor stalls before reaching the second stage, medical intervention with synthetic oxytocin, such as Pitocin, can be used to restart and maintain labor progress.