During which phase of labor does dilation occur from 4 cm to full dilation?

The active phase of labor is characterized by the progression of cervical dilation from 4 cm to full dilation, which is 10 cm. This phase typically follows the latent phase and is marked by more intense and frequent contractions that lead to significant changes in the cervix. During the active phase, not only does the cervix continue to dilate rapidly, but the descent of the fetus into the birth canal also occurs.

In contrast, the latent phase involves initial dilation that typically occurs from 0 cm up to about 4 cm and is characterized by longer intervals between contractions and less intense pain. The second stage of labor begins after full dilation is reached and involves the actual delivery of the baby, while the third stage encompasses the delivery of the placenta. Understanding these phases is key for effective management of labor and delivery in clinical practice.