Cervix Lingo: Effacement what? Dilation who?

As a pregnant woman gets closer to the birth of her little one, she will typically have more exams and may be introduced to a whole new vocabulary. When attention shifts from keeping the baby thriving inside to getting the baby safely outside, the cervix becomes a focus of attention.

First things first, the cervix is the lower “neck” of the uterus, and sits at the top of the vaginal canal–which is also referred to as the birth canal. Just as sperm travelled through the cervix and into the uterus for conception, the baby will eventually travel out of the uterus through the cervix during birth. Throughout pregnancy the cervix has been tightly closed and fortified with a mucous plug to keep the baby safe and sound. This all begins to change toward the end of pregnancy and throughout labor. The end result of cervical change is a cervix that is dilated to 10 centimeters and is ready for the second stage of labor: pushing.  There are 5 different cervical changes that occur to get to this point, and each comes with its own lingo.

#1: Position: Posterior, mid-position, anterior

This is a way to describe the position of the cervix in the birth canal (aka the vagina). The cervix starts out in the posterior position, which means it is oriented toward the backside. In early labor the cervix transitions from the posterior position, to the anterior position. Anterior means front of the body and this alignment is necessary for the baby to move through the birth canal.

#2: Consistency: Firm, medium, soft

These sound like descriptions for how to choose fruit, and you know what? That’s not a bad way to make sense of what we’re talking about here. Matter of fact, a soft cervix is often referred to as “ripe,” and prostaglandins, which can aid in the softening of the cervix (for example semen, a natural source of prostaglandins, or cervadil, an artificial source of prastaglandins used in some labor inductions) are sometimes called “ripening agents.” At its most firm, the cervix will feel like the tip of a nose (or perhaps unripe fruit), at it’s most soft, it will feel like lips (or perhaps very ripe fruit).

#3 & #4: Effacement & Dilation: Effacement is measured from 0 % – 100%, dilation is measured from 0 centimeters (closed) – 10 centimeters (complete dilation)

These two definitely require visual aids.

Effacement speaks to the “thinning” of the cervix, while dilation speaks to the opening of the cervix. In the non-pregnant state, the cervix is typically 3 – 5 centimeters long. As labor approaches, the cervix starts to draw up and over the baby’s head thus becoming shorter and thinner. Imagine your baby pulling a turtleneck over his or her head. (Very funny visual, no? And not too dissimilar!)

Dilation is the opening of the cervix from completely closed, 0 centimeters, to completely dilated, 10 centimeters.

#5: Station: -3, -2, -1, 0, +1, +2, +3

Station refers to how high the baby’s head (or other presenting part–for example, the bottom in most breech presentations) is in the pelvis. At 0 station the baby is in the pelvis and considered “engaged.” The lower the baby is in the pelvis, the less distance he or she needs to travel to eventually be born. Starting to push when the baby is too high in the pelvis can lead to maternal exhaustion. There is something called “laboring down,” in which mama sits tight at 10 centimeters allowing the uterine contractions (vs her active pushing) to do the work of bringing the baby further down into the birth canal. This can be a great way to be efficient with both mama and baby energy, and to save up all that pushing power for when it’s really needed.

How to use your newfound cervix lingo

Why is this knowledge useful? First of all, it is just nice to feel like you know what the heck your practitioner is talking about, right? Second of all, you may want to write down whether you are soft or firm, closed or a little dilated, and all the rest to share with your doula. This information is useful to us so that we can remind you of the progress you have made toward birth. Thirdly, if your practitioner starts talking with you about an induction, and it is something you are considering, this information takes on a special importance. There is something called the Bishop Score which assesses cervical favorability based on the 5 cervical qualities you have just learned. Want to know more? It’s all right here.