What are the stages of labor and what happens in each?

Labor has four stages. Stage one begins with regular contractions and cervical dilation and ends at complete dilation of 10 centimeters. It has three phases: latent with slow dilation to 6 centimeters, active with faster dilation from 6 to 10 centimeters, and transition from 8 to 10 centimeters with the most intense contractions. Stage two begins at complete dilation and ends with delivery of the infant, with active pushing. Stage three begins after delivery and ends with delivery of the placenta, usually within 30 minutes.