What marks the beginning of the second stage of labor?

The beginning of the second stage of labor is marked by full cervical dilation, which occurs when the cervix has opened to a diameter of 10 centimeters. This stage is critical as it signifies that the body is ready for the baby to be delivered. Once the cervix is fully dilated, the mother experiences strong and frequent contractions, which aid in pushing the baby down the birth canal.

The second stage involves the actual delivery of the infant, which occurs shortly after the cervix is fully dilated. Factors such as the positioning of the baby and the strength of the contractions play significant roles during this stage. The other events mentioned, like the water breaking or the delivery of the placenta, occur before or after the second stage and are part of the overall labor process; therefore, they do not define the transition into the second stage.