The 3 Ps act independently, so a change in one cannot affect the influence of another.

The slides state that the three factors **interact** to determine progress and outcome. For example, effective contractions may not produce descent if fetal position or pelvic dimensions present an obstacle. The framework is useful precisely because labour depends on the combined relationship among its components. **Key takeaway:** Labour progress reflects interaction among Power, Passenger, and Passage.\n\n**Glossary:** **Descent**: movement of the presenting part through the pelvis.