North American Registry of Midwives (NARM) Practice Exam

Which phase of the active labor denotes the period of most rapid dilation?

1. Acceleration phase

2. Deceleration phase

3. Transitional phase

4. Peak phase

The correct answer is: Acceleration phase

The active labor phase is characterized by a significant increase in the frequency, intensity, and duration of contractions, leading to cervical dilation. The acceleration phase specifically marks the time during which dilation occurs most rapidly, typically progressing from about 4 cm to around 7 cm. This phase often involves strong and closer contractions that help facilitate quick and efficient opening of the cervix, providing an essential transition toward the next stages of labor. This understanding underscores the description of the acceleration phase as a critical period where the laboring person experiences the most pronounced and swift change in cervical dilation. It is important to recognize the nature of contractions during this time, as they dramatically influence the labor process and can have implications for both maternal comfort and fetal well-being. Each of the other options does not represent a phase characterized by rapid dilation in the same manner.