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How Uterine Contractions Work

Throughout your pregnancy, you’ve likely become rather familiar with the term “contractions.” And, depending on how far along you are, you may have already felt some already. Those early Braxton Hicks contractions that made your stomach feel hard and tight are just a warm-up for your uterus. 

Contractions are the muscle contractions happening within your uterus that make childbirth happen! The uterus, which surrounds your baby, squeezes and contracts. Each of these contractions nudges your baby closer to making their grand entrance.  

Contractions make two key events happen before your baby is ready to make his or her debut: cervical effacement and cervical dilation. Effacement is the thinning of the cervix, where dilation is the opening of the cervix. As the baby’s head drops down into the pelvis, it pushes against the cervix. This causes the cervix to relax and thin out (efface). As the cervix thins out, it also begins to open (dilate). 

Once you are 100% effaced and 10 centimeters dilated, you are ready to push. And at this moment, you will be working in tandem with your uterine contractions to finally meet your baby! 

Are you still having trouble imagining how uterine contractions get your baby in position for birth and help him or her progress through the birth canal? 

Picture this: you’ve put a ping pong ball inside of a balloon. You know that in order to get the ping pong ball out (without popping the balloon), you will need to gently work the ping pong ball through the opening of the balloon. You can do so by gently squeezing the balloon from the top. As you squeeze the top of the balloon, pressure builds at the bottom. (You do the same thing when you’re moving toothpaste down a tube). Each time you squeeze the top of the balloon, you create more and more pressure at the bottom. This pressure causes the balloon’s neck to thin out. As the balloon’s neck thins, the area for it to exit gets wider and wider until it can finally come out, leaving the balloon fully in-tact. 

Sounds like magic — but it’s just the amazing female body hard at work.

 Want to see how it would work? Watch the video here: