C is for Cardinal Movements

I am a firm believer that knowledge is power, and that it can be very empowering to learn. New information is a way to expand your horizons and in come cases, check your bias, drop your judgement and be fully present in many situations.

I used to be a doula that was sure had some type of effect on the way that a person’s birth went. I felt responsible for their birth outcomes. I needed to help them fight for their choices because they needed an extra voice talking at their care provider.

I also thought that if I helped clients try different positioning techniques in pregnancy, that the baby would get lined up perfectly for birth. I believed so much in this, that I spent my precious time and money attending workshops to learn all the suggested techniques and positions to have my clients practice during pregnancy. 

Six…almost seven years into this doula gig, and countless births under my belt- I don’t feel the same way anymore. I’ve learned that nothing my clients or I do will alter the way the baby is positioned. This conclusion is based on my own experience and knowledge regarding the birthing person’s standard anatomy and shape.

Essentially, human beings capable of birth have four distinct and differently shaped pelvises. Depending on the width of the inlet of the pelvis, the baby needs to navigate in different ways to maneuver through each one. As the baby’s station (position of the head in relation to the ischial spines) changes, the contractions from the uterus work with the baby’s movements to help it navigate through the pelvis. These movements are called the cardinal movements, which we will discuss below. For reference sake, take note of the different bony landmarks of the pelvis to the right, in order to grasp and visualize how a baby will navigate through a pelvis into the birth canal.

First, the baby engages in the pelvis. Its widest presenting part (usually the occiput- or back of the head- is this part) that drops into the pelvis.

 

 

 

Then, as the head reaches the fleshy pelvic floor, the baby tucks its chin towards it chest to decrease the diameter that is presenting, this is called flexion.  Next, is the descent, the head moves down until it reaches the pelvic inlet.

This is immediately followed by internal rotation, allowing the longest part of the head to line up with the longest part of the mother’s pelvis. Which is the distance from the pubic symphysis to the sacrum. (Baby literally begins turning inside of the pelvis like some kind of synchronized swimming maneuver)

Extension happens when the internal rotation has completed and the head is passing beneath the symphysis pubis (pubic bone) while in flexion. This is usually what takes the longest to happen during the pushing phase, especially with first-time parents.

This leads into external rotation which allows for the shoulders to rotate internally into the pelvis.

The baby’s head then goes into complete extension to lead the shoulders through the pelvis.

 

The baby rotates again beginning restitution.

Finally, when the shoulders (first the anterior, then the posterior) passes under the symphysis pubis its called expulsion.  (If the position is ideal, the baby will get a bit of a Heimlich maneuver where the pubic bone forces amniotic fluid out of the baby’s lungs). A baby is born, a first breath is taken!

 

No matter how a baby is positioned at the onset of labor, as it passes through the pelvis for a vaginal delivery, this is how babies get out. An elaborate and innate wiggle and squirm dance that gets them into your arms.

As doulas, we can increase comfort by suggesting different positions and we can increase relaxation for a laboring person. However, only a baby can work with the anatomy of the pelvis, the power of the contractions and gravity to navigate through a vagina. Occasionally, a care provider can assist with the help of forceps or vacuums, but this isn’t as common as some might think.

At Houston Birth & Baby, we happily cheer you on, and occasionally hold a leg while you are pushing!

Did you learn a thing or two? We’d love to hear your feedback in the comments below! If this was an interesting read for you, and you want to know more about the childbirth process- join us on January 26th for a full day of learning in Tomball. I’ll be teaching all the things about how birth happens, and I’d love for you to be there!

Register today! 

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