Baby Is Coming: What to Know About Cervix Dilation

It’s almost showtime. But first your cervix needs to open so that baby can fit through the birth canal.
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Updated January 25, 2022
pregnant woman sitting in hospital bed while in labor
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It’s no secret that your body will go through some major changes during pregnancy in order to ready itself for labor and delivery. Your vaginal discharge may increase and get thicker, and your bump may drop as baby settles deeper into your pelvis. But one transition that isn’t obvious on the outside is cervix dilation. A few weeks before baby’s anticipated arrival, your doctor or midwife will start checking to see if your cervix has started opening at all (how did you think baby’s head was going to fit through the birth canal?). Suffice it to say, it’ll go from completely closed to wide open. But what exactly does cervix dilation entail, how important is it to labor and delivery and is it possible to speed this process along? Here, we share everything you need to know about cervix dilation in pregnancy and labor.

What Is Cervix Dilation?

During the laboring process, you’ll hear a lot about cervical effacement and dilation, both of which refer to changes that happen in the cervix as the body prepares to deliver baby. Towards the end of pregnancy, as labor approaches, the cervix must thin and open to accommodate baby during delivery.

Dilation in pregnancy is the widening of the cervix, while effacement is the thinning of it. Cervical dilation is measured in centimeters, with 0 centimeters being completely closed and 10 centimeters (the approximate width of a newborn’s head) being fully dilated. The cervix must be fully dilated in order for a mom to begin pushing baby through the birth canal.

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Cervix Dilation Symptoms

The American College of Obstetricians and Gynecologists (ACOG) explains that the cervix can begin dilating a few days before labor truly begins. At this point, most women won’t notice any physical cervix dilation symptoms. But one big tip-off that dilation has started? You might lose your mucus plug; this is a clump of thick mucus that blocks the opening of the uterus during pregnancy. As the cervix begins to open, the mucus plug dislodges and comes out like discharge.

Once things start heating up and labor is officially underway, you’ll begin to notice more signs of dilation. You won’t be able to feel the cervix opening, explains Denae Ellson, CNM, a certified nurse midwife in Edina, Minnesota, but what you will feel are the uterine contractions that work to stretch the cervix open. “As the uterus contracts, it pulls the cervix up slowly and steadily, which results in it opening wider,” she says. Just how painful these contractions are varies from woman to woman.

How to Check Cervix Dilation

If you have an uncomplicated pregnancy, your doctor or midwife will typically start checking for dilation after the 36-week mark, notes Ellson. You’ll also be examined throughout your labor experience to see how things are progressing. You can expect to be checked by hand; practitioners are all trained to measure the opening of your cervix with their fingers, explains Nicole Williams, MD, an ob-gyn practicing in Chicago, Illinois.

To check the cervix, Ellson says that “providers place two gloved, lubricated fingers into the vagina and reach up until their fingers can touch the cervix; then with the two fingers we measure how wide the opening is.” These exams shouldn’t be painful, but they may be a bit uncomfortable.

Since this is a manual exam, it’s technically something that can be done at home. However, checking your own cervix comes with the risk of spreading bacteria to the area, which can cause infections and complications. What’s more, unless you have medical training, it’s hard to know exactly what you’re feeling for. It’s best to talk to your doctor or midwife before taking matters into your own hands, so to speak; they may be able to show you how to check cervix dilation and effacement in a safe and useful way (or they might advise you to skip this step altogether).

How Dilated Can You Be Without Being in Labor?

So much emphasis is put on cervical dilation during the labor process, but you can actually start dilating weeks before Delivery Day—so if your doctor says you’re 1 centimeter dilated at your 38-week checkup, don’t assume that baby is on the way. “I’ve seen patients become dilated about 3 or 4 centimeters without active labor,” says Williams. “They’re usually in their late third trimesters.”

On the flip side, it’s also normal for the cervix not to be dilated at all before labor. So don’t worry if you’re 40 weeks along and still measuring at 0 centimeters; your body could still be preparing for labor and delivery in other ways. Dilation is just one piece of the puzzle in the laboring process. “Dilation alone doesn’t really mean much until you’re in labor,” says Ellson. “When we do a cervical check, we’re looking at more than dilation. We’re looking at how soft it is, its position and how open it is.”

Having a dilated cervix near the end of pregnancy is usually no cause for concern—your body is just progressing towards the finish line. However, if your cervix starts to dilate too early, it could be a sign of preterm labor, which could require further evaluation and even hospitalization, according to Williams. There are a variety of reasons the body may go into preterm labor, but if it’s specifically a cervical issue, it may be caught on an ultrasound before any dilation actually begins. Ellson explains that sometimes “the cervix just isn’t capable of staying closed because of the weight of the pregnancy,” which can cause it to start dilating as early as the second trimester. The good news is that this is rare, and it’s often identified early enough that you and your doctor can develop a plan.

How to Dilate Your Cervix Faster

We get it—you’re eager to get this on the road. Unfortunately, there isn’t a whole lot you can do on your own to make your cervix dilate faster. Still, while there’s no sure-fire way to expedite labor, Ellson says there are a few steps you can take “to help tip the scales” and nudge things along by a day or so.

In order for your cervix to dilate, you need strong uterine contractions. Ellson explains that the best way to get these going is by supporting the natural release of oxytocin in the body. Here are some ways to do this:

  • Move your body. A study found that women who participated in regular water exercise throughout pregnancy experienced shorter first and second stage labor than those who were not active in the same way. Light exercise during early labor can also help. Ellson explains that movement can boost oxytocin, which will lead to stronger contractions and quicker cervical dilation. In other words, as those regular contractions start to kick into gear, consider doing some low-intensity exercises to dilate the cervix faster, or just go for a walk while you still can.

  • Try having sex. While there’s no solid consensus, some research and ample anecdotal evidence have associated sex around the time of your due date with cervical changes that can ultimately kick labor into gear. The prostaglandins in semen can potentially help with effacement, while a release of oxytocin from an orgasm can get dilation-causing contractions going. Having sex late in pregnancy is generally considered safe; however, some moms-to-be with certain risk factors may have to abstain, so check with your doctor or midwife to get the green light.

  • Nipple stimulation. If you’re past your due date and get approval from your provider, Ellson says you can help your cervix get ready for labor and trigger your body’s natural oxytocin release by stimulating the nipples with hand expression or pumping. Be aware though that nipple stimulation can cause particularly intense and prolonged contractions.

  • Evening primrose. Ellson says another option is to “place a capsule of evening primrose oil into the vagina to soften the cervix and encourage it to be more receptive to labor contractions.” This technique is somewhat controversial, though, and research has shown that it’s not necessarily effective. Again, check with your provider before moving forward with this method.

Reasons Your Cervix Isn’t Dilating

If you’re approaching your due date (or are there already) and your cervix isn’t dilated, the simple reality is that your body is just not in labor yet. Both Williams and Ellson say that no one really knows what specifically triggers the body to go into labor or why the cervix doesn’t always dilate completely. It’s possible your contractions just aren’t strong enough to pull the cervix open.

If things aren’t happening naturally, your doctor may want to induce labor. Depending on the situation, they’ll likely start out conservatively with physical interventions like a manual membrane sweep or a Foley catheter (this is essentially a balloon to dilate the cervix). There are also different medications that can help induce labor and expedite dilation to varying degrees, including Pitocin (the artificial form of oxytocin). If none of these options get the cervix to fully dilate, Williams says a c-section may be necessary.

Remember, cervical dilation is an important part of the laboring process, but there are also other pieces that have to fall into place for the body to be ready for delivery. So whether you’re walking around 2 centimeters dilated for a week or feeling discouraged because you aren’t dilated at all as your due date approaches, try to relax and trust that your body will get there (eventually) and baby will come—one way or another.

About the experts:

Denae Ellson, CNM, is a certified nurse midwife at Southdale ObGyn in Edina, Minnesota. She earned her bachelor of science in nursing from the University of Wisconsin and her master of science in nursing from Georgetown University in Washington DC.

Nicole Williams, MD, FACOG, FACS, is a board-certified ob-gyn and founder of The Gynecology Institute of Chicago. She is also the author of This Is How You Vagina. Williams earned her medical degree from the Stritch School of Medicine at Loyola University of Chicago in Illinois.

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.

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