What is the correct sequence of the stages of labour?

• A. Engagement, Descent, Flexion, Internal rotation, Extension, External rotation and Expulsion
• B. Engagement, Descent, Extension, Internal rotation, Flexion, Expulsion
• C. Descent, Engagement, Flexion, Internal rotation, Extension, Expulsion
• D. Engagement, Descent, External rotation, Internal rotation, Extension, Expulsion

Answer: (A)

During labor, the baby moves through the pelvis by a defined sequence called the cardinal movements. The progression is engagement, descent, flexion, internal rotation, extension, external rotation, and expulsion. Engagement is when the widest part of the presenting head sits at the pelvic inlet. Descent carries the head deeper into the pelvis. Flexion brings the chin to the chest so the smallest head diameter presents first. Internal rotation aligns the head with the pelvis’s long axis to pass through the midpelvis. Extension occurs as the head negotiates the pubic arch and crowns. External rotation (restitution) rotates the head to align with the shoulders, allowing the rest of the body to be expelled. This order best describes how the head and body navigate the pelvis; rearranging steps would disrupt the coordinated passage through the birth canal.