understanding cervical changes during labor
There is, in my opinion, an unfair amount of focus on the state of someone’s cervix as they near the end of pregnancy. Your provider might offer to perform a cervical check. Friends and family might start asking if you’re dilated yet. You might start to feel like a watched pot, with everyone holding their breath. The stress of this might actually prolong the start of labor.
Cervical dilation is only one piece in the puzzle of birth. I’ve known folks who were 3cm dilated for weeks before they felt a surge. Conversely, I’ve also been at a birth where someone was found to be 6cm dilated and had her baby fifteen minutes later. You can see how dilation alone is not a clear indication of progress. Measuring dilation is also not an exact science. The size of a provider’s hands plays a part, as well as their level of experience.
A cervical check is never a necessity. You may decline one or request one at any time. It can never tell you when your baby will be born. All it can give you is a snapshot of what is happening in that moment. If you do consent to a cervical exam, there are four other factors your provider assesses in addition to dilation - cervical effacement, cervical consistency, cervical position, and fetal station. These five factors taken together are what’s known as the Bishop score. Let’s take a closer look at each one.
Cervical Dilation. Cervical dilation is how dilated or open your cervix is. Measured in centimeters, it ranges from 0-10 and is assessed by your provider during a cervical or vaginal exam. It is worth noting that your cervix doesn’t dilate in a perfect circle. It actually opens in more of an oblong shape in a back to front direction. It is common for the last bit of your cervix to remain over your baby’s head, sometimes right up until you feel the urge to push. Your provider may call it an “anterior lip.” They may offer to push it back manually. This is a painful process and you can choose to decline it.
Cervical Effacement. Effacement is how thin your cervix is and it will be given as a percentage. 0% would mean your cervix is still quite thick and in a pre-labor state. 100% means your cervix is paper thin.
Cervical Consistency. If you are a practitioner of the Fertility Awareness Method (FAM), you may already know a bit about cervical consistency. As your body prepares for labor, your cervix will soften. This is something you can check for yourself! A firm cervix feels kind of like the tip of your nose. If your cervix is soft, it feels more like your earlobe.
Cervical Position. Again, if you are familiar with FAM you may know something about cervical position. The cervix can move between a posterior position (facing backwards towards your rectum) and an anterior position (facing forward towards your vagina). As labor progresses your cervix will move into anterior position.
Fetal Station. Your baby’s position in your pelvis, or station, is an important indicator of progress. Negative numbers (-3 to -1) indicate your baby is “floating” in the inlet of your pelvis. 0 station means your baby is fully engaged in the middle of your pelvis, level with a bony prominence called the ischial spines. Positive numbers (+1 to +3) indicate your baby has entered the birth canal. This is something you could also try and measure for yourself, especially if you get familiar with it before labor begins.
These numbers, your Bishop score, can help determine whether or not an induction is likely to be successful.
Now, what exactly do all these things mean for you, the birthing person? If and when you consent to a cervical check, I encourage you to ask for station and effacement as well as dilation. Effacement and station may be a better judge of your progress than dilation. If you are 8cm dilated but your baby is still at -1 station, that means your baby still has to navigate through your pelvis and into the birth canal.
I like to encourage my clients to get familiar with their cervix during pregnancy. You may be able to notice some of these changes yourself as you near the end. It is far less invasive - and maybe even enjoyable - if you do this yourself rather than allow your provider to check.
If you have no desire for cervical checks during labor, there are other ways to gauge your progress - read more here!
