The third stage of labour involves the birth of the placenta and can be managed either physiologically or actively. Physiological management relies on natural processes to expel the placenta within 60 minutes, while active management involves administering oxytocics, early cord clamping, and controlled cord traction to deliver the placenta within 15 minutes. Examining the placenta and membranes after birth ensures they are complete and rules out any abnormalities. Potential placental anomalies include succenturiate lobes, velamentous cord insertion, and battledore or circumvallate shapes.