First off, pregnant mama, let me just say that you are incredible. You’ve got a beautiful (albeit big) pregnant belly - an approximately 7 pound baby hanging out in there until it is cooked to perfection and ready to exit. You have a pelvis - one that probably hurts a lot as your due date nears. And you have a vagina that is somehow going to expand enough to let this babe out. Ever wonder how all these pieces are going to work together to complete the miraculous journey of birth? Allow me to demystify the process.
So that organ you grew from nothing during the first 4 months of pregnancy - the placenta - produces a hormone called relaxin toward the end of pregnancy. As you might guess from the name, this hormone relaxes your muscles, joints, and ligaments - particularly the joints of the pelvis. While this can contribute to aching hips, pubic pain, and the infamous “pregnant waddle”, relaxin allows the pelvis to stretch and change diameters during the birth process. This in turn helps your baby make the snug fit through.
As the pelvis flexes to allow baby to squeeze through (you can read more about that here), your baby does considerable work on her end. Incredibly enough, her head is beautifully designed to fit through the pelvis. It is made of up of a set of bones that can temporarily overlap to allow baby’s skull to decrease in diameter. This often leads to the infamous “cone head” that some babies have for the first few days after birth.
And we can’t forget the vagina and its role in the birth process. The vagina is an elastic, muscular canal with a soft, flexible lining. The relaxin produced by the placenta prepares it to stretch easily, but as a muscle it is already made to stretch and recoil (so yes, you will be moreorless the same “down there” after giving birth). As the baby is slowly pushed through the birth canal, the vagina stretches with it, allowing the process of birth to complete.
So go ahead, give yourself a pat on the back - you are a super woman. You’ve grown a human being in your belly from nothing but a tiny egg and sperm. Now as the last days of pregnancy begin, your body prepares to exit this baby by making your joints and lady parts ready to move and stretch. Let the miracle of birth begin.