Your cervix - before entertaining the idea of getting pregnant, how much time did you spend thinking about your cervix?
If you're like most women, you may have heard or read about it but not put much more thought into it beyond that. Your cervix is capable of doing phenomenal things!
So what does the word "cervix" even mean?
If you guessed 'neck', you would be right! Your "cervix uteri", a medical term used in 17th century Latin, literally means 'neck of the womb' (etymoline, 30 June 2015).
That's right, your uterus has a 'neck' that opens to allow your baby to pass through much like the collar of a turtleneck sweater.
Before you put it on, you may think your head will never fit through the thickly knitted collar, but as you pull it over your head, the material stretches and thins to allow your head to squeeze through. Your cervix undergoes similar changes as you release hormones and contract your uterus.
1. You Dilate Your Cervix Slightly Each Month
During your monthly cycle, hormones cause changes in your cervix. It may protrude more prominently into your vagina and feel much like the tip of your nose, or it may sit higher up and fell soft to the touch like your lips. The external orifice of your cervix opens slightly both during your fertile phase and menstruation (for visuals, see the Beautiful Cervix Project). In pregnancy, the strong set of muscles that form your cervix is sealed with a thick mucus, a.k.a. your mucus plug, helping to keep your uterus tightly shut (Ina' May's Guide to Childbirth, 2003). In other words, its job is to help to keep baby in and infection out until baby is ready to be born.
So yes, you read that correctly - YOU are an active participant in this process both during your monthly cylce and birth. And by this, I mean that you and your baby work as a team to dilate your cervix (you provide the hormones and contractions and your little one is helping right along by getting into a good position and exerting pressure from within). Cervical dilation is not something that just "happens" to you, it is the first of many times in your life that you and your little one collaboratively work together toward a common goal - finally meeting face-to-face after all of those months of shared intimacy in your belly.
2. Your Cervix Looks Different after Childbirth
Who would have thought? Yes, after giving birth or having a procedure requiring cervical dilation, the opening of your cervix is actually shaped differently! Picture a fluffy pink bagel in your mind. Sometimes bagels take on a round dimple or hole in the middle and sometimes there is horizontal slit across your bagel. Before birth, your cervix looks more like the dimpled bagel; after birth, your cervix more closely resembles the bagel with the H-shaped slit in the middle. It is pretty remarkable, indeed. By examining your cervix, healthcare professionals are able to tell whether or not you have previously had a baby or a procedure.
The cervix as it is seen pre vaginal delivery (left), with a rounded os, and post vaginal delivery (right), with a linear or horizontal os.
3. Your Cervix Does Not Dilate Concentrically to 10cm
Contrary to what you may have learned while researching childbirth, your cervix does not dilate neatly in concentric circles from 0cm to 10cm. Toward the end of pregnancy, the cervix in most women is positioned such that the opening is slightly tilted toward her backside (described as posterior). As your baby and body begin to labor and the hormones and contractions you produce allow your cervix to open in the form of an ellipse (the shape of a somewhat flattened circle). In her blog, Midwife Thinking, Rachel Reed provides a particularly helpful diagram for visualizing how the cervix opens during childbirth. To view this image, please click here.
So, what do you mean my cervix doesn't dilate to 10cm?
Assigning a numerical value to the extent to which your cervix is opening is a way for providers to observe and communicate to one another what your cervix is doing at the exact moment they are doing a pelvic exam. They use these numbers as an orientation to see how close your cervix is to having completely thinned out and been pulled back to allow your baby to pass through into the birth canal. So 9cm is not actually measuring the space between the sides of the oval, rather it is your providers way of communicating that there is just a little bit of cervix left before it has been completely pulled open through the work of your hormones and contractions. For a clear explanation, visit this blog by doula Suzanne Deselms. To read about why vaginal exams are done, when they may be considered necessary and what you can discuss with your provider, check out this piece by midwife Brenda Manning.
See how your body and baby work to help you open your cervix (starting at 14 seconds):
4. Your Cervix Can Open and Close during labor. What?!
Yes, that's right. Your body has the ability to open and close your cervix. It opens and closes minimally during your monthly cycle, it closes after birth, so why would we think it only opens during labor? If you have already had a baby or chatted with someone who has, you might have experienced or heard about nurses, midwives and/or doctors coming up with different measurements. Surely, a probable explanation for this occurence is the fact that this method of assessing how wide the cervix has opened is subjective. What about when the same provider comes up with different measurements? Is that even possible?
The answer is... yes! Your body is that spectacular! And why shouldn't it be? After all, for our species to ensure the safe arrival of our young, it is important to give birth in a place we feel is safe. So if you find yourself feeling uneasy or uncomfortable during labor, it may be your body and mind's way of helping to remind you to settle back in and find your safe place. Other care providers and midwives, like Ina May Gaskin, have actually observed this phenomenon on multiple occasions. Ina May Gaskin wrote the following about a laboring woman, who at one point in her labor held her body in a particularly tense way for the duration of an intense contraction (Ina May's Guide to Childbirth, 2003: p. 138):
"That was when I made my thrilling discovery--that her cervix had cinched down from eight centimeters to about half that amount. Having been with her continuously throughout her labor, I knew that she had done it with her mind, because she had been sitting rather still as it happened."
For more on the little known or acknowledged phenomenon of cervical reversal, have a look at Lois Bowman's summary on www.birthworks.co.za. There are also other anatomical factors which may possibly underlie changes in measurement such as cervical swelling. the position in which the mom is in and the breaking of waters.
5. Cervical Dilation - It's Not a Race
Did you know that it is now common knowledge that women today have longer labors? Read about it here (if you are short of time, skip down to the question: "How can it be that we're just now finding out what's a normal length of labor?"). Specifically, how fast a laboring woman dilates her cervix today is very different to how fast a one Dr. Friedman observed dilation among a small group of women in the 1950s. Your care provider may be using this outdated method, known as Friedman's Curve, to make judgements about whether or not your labor is progressing as "fast" or "normal" as they think it "should" be.
Your cervix is by no means a crystal ball. When you agree to a vaginal exam to check dilation there is still no way of telling when your body and your baby will be ready for labor or even how much longer you must wait to meet your baby when you are actually in labor. Any time you consent to a vaginal exam, the information you obtain regarding the dilation of your cervix is just a snapshot of what your cervix is doing at that one point in time. It tells you nothing about the work you and your contractions have done in order to prepare your baby and your body for birth. Your contractions are not only responsible for helping to open your cervix, they help baby to move into position and to prepare for birth.
While there are plenty of textbooks on childbirth, none of them hold the answer to exactly how you, your body and your baby need to labor. Each mother brings to the birth of her child her own set of personal, emotional and physical experiences that set the stage for labor to play out. We birth differently because each one of us is unique. The American College of Obstetricians and Gynecologists (ACOG) is currently discussing the revision of its current guidelines in order to reduce the number of first-time cesareans. In particular, many are moving toward considering a 6cm dilation of the cervix to be the start of active labor rather than the current guidelines of 4cm.