Cervical checks aren’t the most fun. They can be pretty uncomfortable and even painful for most women. But when your doctor or midwife says it’s time to check your cervical progress, it’s important to understand what the numbers mean. 2 cm, 80%, and -2 . . . what?! Let’s break it down and talk about effacement, dilation, and station and the importance of each when getting a cervical check.
What Is Effacement?
Normally, before pregnancy and during the early months of pregnancy, your cervix is long and firm. It’s around 2 to 3 cm long. Effacement (measured in percentage) is the process of your cervix becoming thinner, softer, and shorter. In late pregnancy or early labor, Braxton Hicks contractions start to shorten (efface) your cervix. Once your cervix has shortened to 1 cm, it’s 50% effaced. As you can see in the diagram above, it’s our goal to reach 100% effacement so there’s no cervix left.6
As most women discover toward the end of their pregnancy, effacement often begins before the expecting woman goes into labor. When your care provider does a pelvic check, they may say your cervix is soft. Or they may even say a certain percentage of your cervix is effaced. It’s good to know that number. Your care provider will also state the dilation of your cervix at this time. Most people focus on the dilation number, but effacement is just as important. But first, what is dilation?7
What Is Dilation?
Once your cervix has effaced (thinner and softer), it begins to open, which is dilation. Our cervix is the opening of our uterus, which is usually tightly shut. Braxton Hicks contractions can cause your cervix to dilate before active labor begins. This is why you sometimes hear about women being 3 cm dilated but not yet in labor. Or you could be on the other side of the spectrum, and your cervix can be firmly closed until you’re in active labor. Both experiences are entirely normal. It’s not until regular contractions begin (when your contractions are at least five minutes apart, each is about one minute long, and that’s going on continuously for at least an hour) that your cervix will begin to open (dilate) more.8,9
As I stated, dilation tends to be the number people focus on the most because they know they must be 10 cm before pushing out their baby. While dilation is an important part of your cervical check, it isn’t the only factor that matters. Cervical ripening involves both softening and thinning of the cervix in addition to cervical dilation. So, paying attention to your entire cervical exam is important.6
For example, I’ve had clients in labor who were declared 5 cm dilated and 70% effaced, and then after two hours, they were rechecked and still 5 cm but 90% effaced. When that happens, people become frustrated because they’re still only 5 cm. But they forget that their cervix is getting thinner, which is required before it can reach 10 cm. Going from 70% to 90% is still good progress, so you shouldn’t feel discouraged!
What Is Active Labor?
You may also be wondering when it’s considered active labor. The American College of Obstetrics and Gynecology (ACOG) states that 6 cm dilation is when you’re no longer in early labor and are now in active labor.1,2 At this time, your contractions will be noticeably longer, stronger, and closer together.2
How Is Dilation Measured?
Care providers measure dilation with their fingers.3 One finger inside your cervix is 1 cm, two fingers in your cervix are 2 cm, and they slowly start to spread their index finger and middle finger to continue to measure to 10 cm. This is why checking for dilation is subjective! Everyone has different-sized hands, so one person might think you are 7 cm while another claims you are 8 cm.
At 10 cm, your cervix is paper-thin (100% effaced), no cervix is left, and you’re fully dilated, which we call “complete.”3,7 For a better understanding, 10 cm is about the size of a softball or a baby’s head.
What Is Station?
Most care providers won’t even say the baby’s station aloud during a cervical check. The “station” of a baby refers to the position of your baby’s head in relation to your pelvis. They record this as a number between -5 (minus five) and +5 (plus five). Zero station means the head is “engaged” on the cervix and has entered the vaginal canal within the pelvic bones. A negative number (-5 to 0) means your baby’s head isn’t engaged in the pelvis.6
During labor, it’s common for a baby to be at -3, -2, or -1. A positive number (0 to +4) means that your baby’s head is moving down the pelvis, and +5 means your baby is crowning (being born). Ideally, you should not push until the head is engaged in the pelvis (at least 0 station), but waiting until the baby is lower in the pelvis is even better. This will help decrease your pushing time and reduce your chances of swelling.4
Is a Cervical Check Necessary?
I want all women to know you can refuse cervical checks. But the only two that you can’t get away from are:
- When you first get to the hospital (they need to make sure you’re really in labor and you’ve made progress)
- Check that you are complete (10 cm, 100%) so you can begin pushing
More cervical checks could lead to a slight risk of infection if your water has been broken, according to one study.5 Whether you get a cervical check or not, your body will know when it’s ready to have a baby!
The Bottom Line . . .
In labor, it’s nice to know if the baby is getting lower in the pelvis. So if your care provider does a cervical check, ask what your baby’s station is. Knowing the effacement, dilation, and station gives you an overall look at how much progress you’re making and how much more progress your body needs to make to have your baby. However, these do not tell you when you’re going into labor or how much longer your labor will be. Every woman progresses differently. It’s nice to know these to see the progress your body is making, but ultimately, it won’t benefit you or your baby in any way — other than knowing where you’re at in that moment.
I hope these descriptions help you understand more about what the numbers mean and what your care provider is doing and looking for during a cervical check. Here’s to hoping that they are quick and painless!
