|Elvis's pelvis looks pretty wide here!|
I think many of us picture our pelvis as a fixed and immobile structure but that is not the case. It is true that in non-pregnant women (and men) the pelvis is locked, but every pelvis is made up of 4 distinct bones that are held together by connective tissue, cartilage and ligaments. The cool thing is that in a pregnant woman, as the pregnancy progresses and especially during the end of pregnancy and labor, the hormone relaxin is released and works to turn those connections into stretchy soft rubber bands (the midwife Gloria Lemay describes them as being like bubble gum) that allow the pelvis to loosen and to expand so a baby can pass through.
You may have come across a few medical terms for a pelvis: adequate, inadequate (or contracted) or even proven. The term "adequate pelvis" is hardly a ringing endorsement for the powerful pelvis, but contracted is obviously worse and proven seems to hold the pelvis's ability in an attitude of guilty of inadequacy until proven innocent. However, judging the size and ability of a pelvis prior to spontaneous labor is about as helpful as deciding the turtle neck part of a turtle neck shirt is too small to fit over your head before you try to put it on. If a careprovider tells a mom that her pelvis is small, this is a huge red flag that he is setting her up for failure. Probably not on purpose, but it means he may not appreciate the way the pelvis works during labor. He certainly has not taken into account the bubble gum features of the pelvis.
Relaxin is not the only thing that opens the pelvis. The position one's body is in makes a difference as well. Squatting is said to increase pelvic dimensions by 30%. That's a lot! You can experience this simply by standing, placing your hands on the area just below your hips then move into a squat. You can feel that your hands are now further apart than they when you were simply standing. This same thing happens when walking, lunging, walking up stairs etc. A baby's head also opens the pelvis, just as the example of the turtle neck demonstrates something that is pliable will make way for something being pushed through it.
|Don't disrespect the pelvis...this position makes it smaller!|
Induction also interferes with the pelvis's amazing ability to open. Relaxin, that hormone that helps cartilage turn to bubble gum, is released in large quantities in the last days of pregnancy and during spontaneous labor. When labor is induced, the body has not had a chance to finish its production of relaxin. During an induced labor, depending on the circumstances, the body may not get the chemical signals that generally get it to start pumping out this and other labor hormones and therefore the pelvis is not able to reach its full potential. Add in the other limitations, including the aforementioned pelvic closing positioning, that come with an induction and you can see why many times baby simply seems stuck in the pelvis. The pelvis just didn't have the tools to do what it was designed to do.
Allowing the pelvis and the baby to work together in birth produces the best outcomes. So when it comes time to have a baby, think bubble gum thoughts and make like Elvis....swing and tilt that baby out!