During which stage of labor does cervical dilation occur?

Cervical dilation primarily occurs during the first stage of labor. This stage is characterized by the gradual opening and thinning of the cervix, which is essential for allowing the fetus to move into the birth canal. The first stage is further divided into three phases: the latent phase, active phase, and transition phase. During the latent phase, cervical dilation begins, often starting from 0 to about 3-4 centimeters. In the active phase, the cervix dilates more rapidly from about 4 centimeters to 10 centimeters. The transition phase, which is also part of the first stage, occurs when the cervix dilates from about 8 centimeters to fully dilated at 10 centimeters.

In contrast, the second stage of labor begins once the cervix is fully dilated and involves the delivery of the baby. The third stage of labor follows the delivery of the baby and involves the expulsion of the placenta. Therefore, the first stage is critical for cervical dilation, which is why that option is the correct answer.