What event characterizes the third stage of labor?

The third stage of labor is specifically defined by the delivery of the placenta. This stage occurs after the baby has been born and focuses on the expulsion of the placenta and associated membranes from the uterus. It typically begins after the baby's birth and can last from a few minutes up to half an hour, although it may sometimes take longer.

This stage is critical because the clearance of the placenta is necessary to prevent complications such as postpartum hemorrhage. The physiological changes that occur during this stage involve continued uterine contractions, which help to detach the placenta from the uterine wall and assist in its expulsion. Understanding this stage is essential for managing labor effectively and ensuring the health and safety of both the mother and the newborn.