The Seven Cardinal Movements of Labor Explained

Labor and delivery are complex processes that require a thorough understanding of the various movements the baby makes as it descends through the birth canal. In this explanation, we will delve into the seven cardinal movements of labor, which are essential for successful expulsion of products of conception.

Movement 1: Engagement

The first movement of labor is engagement, where the presenting part of the fetus (usually the head) moves into the pelvis and begins to apply pressure on the maternal bony pelvis. This movement helps to initiate the process of labor by stimulating the production of prostaglandins, which soften and dilate the cervix.

Movement 2: Descent

As the presenting part continues to move down the birth canal, it encounters various obstacles, including the pubic bone and the ischial spines. The baby's head molds itself to fit through these narrow passages, a process known as flexion. This movement helps to reduce the size of the fetal head, allowing it to pass through the birth canal more easily.

Movement 3: Flexion

Flexion is an essential movement that allows the fetal head to mold itself to fit through the birth canal. As the head descends, it bends forward and down, reducing its diameter and enabling it to pass through the narrow passages mentioned earlier.

Movement 4: Internal Rotation

After flexion, the fetal head begins to rotate internally, or towards the maternal spine. This movement is crucial for successful delivery, as it helps to align the fetal head with the pelvic outlet, making it easier for the baby to emerge from the birth canal.

Movement 5: External Rotation

As the fetal head approaches the perineum, it begins to rotate externally, or away from the maternal spine. This movement helps to align the baby's shoulders and body with the birth canal, preparing them for delivery.

Movement 6: Extension

During extension, the fetal head extends back towards its original position, allowing the baby to emerge from the birth canal. This movement is accompanied by a sudden increase in pressure on the perineum, which can cause discomfort for some women.

Movement 7: External Application of Force

The final cardinal movement of labor is external application of force, where the mother's voluntary bearing-down efforts help to push the baby out of the birth canal. This movement is crucial for successful delivery, as it helps to overcome any remaining resistance and bring the baby into the world.

In conclusion, the seven cardinal movements of labor are essential for successful expulsion of products of conception. Each movement plays a critical role in guiding the fetus through the birth canal and preparing it for delivery. Understanding these movements can help women and healthcare providers alike better navigate the process of labor and delivery.

7 cardinal movements of labor explained