Chapter 2: BONES & THE PELVIS
Lesson Introduction
During a typical head-first vaginal birth, the baby moves through the curved pelvic passage. The baby's head may engage, descend, flex, and rotate before extending beneath the pubic arch. The shoulders and body then follow.
These movements are commonly taught as the cardinal movements of labor. They offer a helpful framework for learning birth mechanics, but real labor does not always follow a perfectly uniform sequence.
Tips & Tricks
Study the movements in sequence.
A commonly taught sequence is:
Engagement
Descent
Flexion
Internal rotation
Extension
Restitution and external rotation
Expulsion
Use a model. A fetal skull and pelvis model can help you visualize how the head relates to the curved birth passage.
Distinguish presentation from position. Presentation describes the body part entering the pelvis first. Position describes the orientation of the presenting part relative to the maternal pelvis.
Avoid predicting labor from one detail. Engagement does not mean birth is imminent, and one fetal position does not determine the outcome.
Stay within scope. Doulas do not diagnose fetal position, assess fetal station, or perform clinical examinations as part of their doula role.
Recommended Study Links
Use these anatomy references alongside a carefully reviewed educational diagram of the cardinal movements. Clinical references for professionals can be more detailed than a doula needs, so focus on basic anatomical relationships.
Knowledge Check
What is engagement?
What is the difference between presentation and position?
Why does the fetal head often rotate during descent?
What are the cardinal movements of labor?
Why should a doula avoid predicting birth outcomes from a single anatomical observation?
