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All About Dilation: Cervical Dilation Chart

Written by Liesel Teen BSN, RN | Jun 4, 2025 7:00:00 AM

Cervical dilation is one of the most important markers of labor progression. But what exactly does it mean to be dilated, and how can you tell if your body is getting ready for birth?

Whether you're pregnant and curious, close to your due date, or just love learning about birth, this guide breaks it all down for you.

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When do you start dilating?

Cervical dilation doesn’t exactly follow a timeline—it’s highly individualized and can start weeks before labor or not until the day labor begins. For some people, especially those who’ve given birth before, it’s not unusual for you to start to very gradually dilate around 36 or 37 weeks of pregnancy. In others, the cervix remains completely closed until active labor kicks in.

During a routine prenatal checkup in the last few weeks of pregnancy, your provider might offer to check for dilation as part of a cervical exam. It’s not uncommon to hear something like “You're 1 cm dilated,” which can be exciting—but also a bit confusing. 

It’s important to understand that being slightly dilated doesn’t mean labor is about to start. Some people stay at 1–2 cm for weeks, while others go from 0 to 6 cm in a matter of hours once labor begins. Labor truly beats to its own drum. 

Several factors can influence when dilation begins but remember, there are always exceptions to the rules! 

  • Which number baby: First-time pregnancies often see slower early dilation
  • Position of the baby: If the baby is well-engaged in the pelvis, the cervix might start to open earlier, if not, it might be later in pregnancy
  • Previous vaginal deliveries: Those who’ve delivered vaginally before may dilate earlier and more quickly due to a more responsive cervix
  • Pelvic shape and size: Mama’s anatomy might impact dilation timeline
  • Baby’s size: a larger baby may require more time to dilate

It’s also worth noting that cervical checks, while informative, are not always predictive. A cervix that’s closed and firm one day can become soft and dilated the next. Conversely, early dilation doesn’t necessarily mean labor is imminent.

How dilated are you when you lose your mucus plug?

The loss of the mucus plug can be an early sign that the cervix is softening or beginning to dilate. However, it doesn’t always mean labor is imminent. Some people lose their mucus plug at 1–2 cm of dilation and still don’t go into labor for days—or even weeks.

Can you feel your cervix dilating?

One of the most common questions late in pregnancy is whether you can actually feel your cervix opening as your body prepares for labor. The short answer is: not usually—but sometimes, yes.

For most people, cervical dilation is a silent, subtle process. In the early stages, you might not feel any clear signs that your cervix is changing and that’s because the cervix itself doesn't have a dense concentration of pain receptors.

Some people feel cramping or lower back pain, while others feel nothing at all. Occasionally, you might notice some vaginal pressure or irregular contractions as the cervix starts to open, but these signs are not always reliable indicators.

While it’s tempting to track every little sensation and tie it to dilation, the truth is that the cervix can be quite unpredictable. What one person feels at 3 cm dilated might be very different from someone else at the same stage. Trust your body, and don’t stress if you’re not feeling anything specific—labor often progresses just fine with or without early signs.

How to know if you’re dilated without checking

While a cervical exam is the only way to know for sure how dilated you are, there are some signs and clues your body might give you—though they’re not always reliable or consistent. 

You may notice signs like increased vaginal discharge, loss of your mucus plug, or stronger Braxton Hicks contractions. That said, these symptoms are not definitive proof of dilation. The only way to confirm dilation is through a physical cervical exam, usually done by a healthcare provider.

 

Checking dilation at home

While it's possible to check dilation at home, it’s not recommended unless you're trained in how to do it. There are risks of introducing bacteria, causing discomfort, and simply not knowing what you are doing. 

I’m gonna be honest with you here for a sec. It took me a looong time and a lot of cervix checking to feel confident in what I was feeling. I won’t say it’s impossible to do but without training and experience it is very difficult to accurately check cervical dilation. And to check your own cervix? That’s a whole other story. 

Moral of the story? As a labor and delivery nurse with over 10 years of experience, I do not recommend checking for cervical dilation at home unless it is being done by a trained medical professional. If you have further questions or feel strongly about this I definitely recommend talking with your medical provider about it.

Purple line dilation

The “purple line” is a fascinating and lesser-known method some birth professionals use to estimate cervical dilation—without doing a cervical exam. It’s a non-invasive visual indicator that appears as a purplish or reddish line extending vertically from the anal area up between the buttocks. As labor progresses and the cervix opens, the line is said to grow longer and darker.

While not part of standard medical training, the purple line has gained attention in midwifery and home birth communities as a potential tool to track labor progression—especially when vaginal exams are not preferred or practical.

The theory is that as the baby descends into the birth canal and pressure increases in the pelvis, blood flow and vascular pressure cause a visible change along the sacrum. This change appears as a purplish hue along the intergluteal cleft (between the buttocks).

The purple line is intriguing and while it shouldn’t replace professional assessments when needed, it can be a useful and empowering tool in the right context—especially for those seeking minimal-intervention births.

If you're curious about using the purple line as a labor cue, talk with your provider or midwife in advance to ensure you're both on the same page about your birth preferences.

Fingertip dilation

“Fingertip dilation” is a common term used in the OB world to describe the very beginning stages of cervical opening. It typically means the cervix is just slightly open — less than 1 centimeter — you can only get the tip of a finger in there.

This is often the first measurable change in cervical dilation. While it may be exciting, it can still be several days or weeks until true labor begins.

Cervix dilation chart

A cervix dilation chart shows how the cervix opens from 0 to 10 centimeters. Here’s a quick breakdown:

  • 0 cm: Closed

  • 1–2 cm: Early labor (may last hours or days)

  • 3–4 cm: Active labor is starting

  • 5–7 cm: Active labor

  • 8–10 cm: Transition phase—getting very close to pushing!

Visualizing dilation with items (e.g., a Cheerio for 1 cm, a bagel for 10 cm) can help people understand what’s happening inside their body.

 

 

What it all means

Cervical dilation is just one piece of the labor puzzle. It’s important, but it doesn’t always predict when labor will start or how it will progress. Some people dilate gradually over weeks, while others go from 0 to 10 cm in hours. Keep in mind that dilation should always be interpreted alongside other signs like effacement, baby’s station, and contraction patterns.

And remember, you’re gonna rock this, mama! 💪