The Meaning of Cervical Dilation and Signs You're Dilating

What does it mean for your cervix to dilate and efface, and can you tell it's happening? We break down what cervical dilation is, and what signs of dilation to look for.

pregnant woman at doctor
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Have you ever wondered what it means for your cervix to dilate or efface? Or what about the signs your cervix is dilating? If so, you're not alone!

Dilation and effacement are terms that doctors and other birth professionals use to describe specific changes in the cervix required for vaginal birth. Even if you've heard these terms, you may not fully understand what the process entails—or know the signs that you're dilating.

First things first: The cervix is the cylinder-shaped tissue at the bottom of the uterus that connects the uterus to the vagina. The cervix acts like a "portal" to the uterus, and during pregnancy, it's filled with a plug of mucus to protect the fetus from the outside world. In preparation for delivery, the cervix thins out (effaces) and opens up (dilates) to allow the baby to pass through the birth canal.

Keep reading to learn more about cervical dilation and effacement, signs you're dilating, and how to check when it's happening to you.

What Is Cervical Effacement?

Cervical effacement happens when your cervix thins and stretches to prepare for vaginal delivery. This process typically begins before signs of dilation occur. Effacement is caused by the baby's head dropping into the pelvis and pressing against the tissue as well as hormonal shifts that ready the body for childbirth.

Doctors track cervical effacement through percentages: A cervix that is 100% effaced has gone from the shape of a thick-walled cone to that of a flat, thin cup beneath the baby's head. When you are fully effaced (at 100%) and fully dilated, you're ready to push.

If you're 50% effaced, that means you're halfway there, says Laura Riley, MD, an OB-GYN and maternal-fetal medicine specialist at Weill Cornell Medicine in New York. Some people, especially those who have given birth before, may have some degree of cervical dilation and/or effacement well before their due date. Still, you will need substantial cervical changes to be considered "in labor."

In other words, even if your health care provider tells you that your cervix has started effacing, it's not until you become more effaced and more dilated that it means labor could be starting.

What Is Cervical Dilation?

Dilation is characterized by an opening of the cervix, which allows the baby to move from the uterus to the birth canal. There's no set time frame for dilation; it can start weeks, days, or hours before labor begins. Contractions will gradually open your cervix to that magical dilation measurement of 10 centimeters.

When your cervix has dilated to that point (about the width of your hand) and your baby's head has descended far enough down, your midwife or obstetrician will tell you that it's time to push and deliver your baby.

Signs of Cervical Dilation

Can you feel your cervix dilating? Usually not, says Ashley Brichter, a doula, lactation consultant, and founder and CEO of Birthsmarter, which offers in-person and virtual childbirth classes. However, while you might not feel the cervix itself opening, there may be other signs that your cervix is effacing and dilating.

Here are a few signs of dilation to look for.

You lose your mucus plug

During pregnancy, a glob of mucus acts as a barrier to the cervical opening, and it protects your baby from outside dangers like infections. As effacement and dilation progress, you may notice your mucus plug pass through the vagina. The mucus plug usually looks like a thick, gelatinous, yellowish-white substance, and it can also be tinged with blood.

You have bloody show

As delivery nears, the blood vessels in the cervix capillaries will rupture, tinting your vaginal mucus with blood. This is called bloody show. You might notice this blood-tinged discharge when you use the bathroom, wipe, or even as discharge in your underwear.

While you'll always want to check with your doctor if you have bleeding during pregnancy, a small amount of bloody show can signal changes in the cervix that mean labor may start sooner rather than later!

You are experiencing pelvic discomfort

Pain associated with dilation is extremely rare. However, pregnant people may feel a small pressure or discomfort from cervical dilation and effacement, says Brichter. While your cervix is dilating, you may also feel backache or abdominal pain similar to menstrual cramps. You also might feel sudden shooting pains in the vaginal area, called "lightning crotch." Lightning crotch is caused by pressure on nerves in the pelvic area.

You are feeling irritable

Going through labor (and the process of cervical dilation) is taxing on the body and mind, so you may be feeling less calm or easygoing than normal. Some pregnant people who are laboring and experiencing significant cervical dilation will be more agitated, sensitive, or irritable. This makes sense as they are focused on what is going on with their bodies rather than on social niceties.

How to Know if Your Cervix Is Dilating

It's pretty difficult to check for cervical dilation on your own, and it's not something you need to do. Your health care provider, however, may begin checking your cervix for effacement and dilation at your prenatal check-ups late in the third trimester. Alternatively, if you're having contractions and head to the hospital or birth center, the medical staff will check your cervix for dilation before admitting you.

During a cervical check, the health care provider will insert gloved fingers into your vagina to manually feel your cervix and determine how thin and open it is. Note, however, that even if your cervix has started to thin and open, when you'll actually go into the active labor phase is still a mystery.

If your cervix isn't dilating as expected, you can often just give it more time and it will happen naturally. Alternatively, depending on your individual circumstances, your provider may use various techniques to help move things along. This is called cervical ripening, which involves stimulating the cervix mechanically or with medicine.

In general, though, once active labor begins, the average progress is about 1 centimeter of dilation per hour for your first baby and 1.5 centimeters per hour for a second baby, according to Dr. Riley. The good news is that while the first phase of labor can take some time (especially for first pregnancies), once you've started dilating beyond the first few centimeters, it means you're well on your way to welcoming your baby.

Key Takeaways

Cervical dilation is when your cervix opens to allow the baby to travel through the vaginal canal and be born. Signs that you're dilating include losing your mucus plug, having bloody show, abdominal discomfort, and backache. By the last several weeks of the third trimester, your medical provider may check your cervix to determine how effaced (thinned) and dilated (open) your cervix is at prenatal visits. Once your cervix is fully effaced and dilated, you're ready to push!

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Sources
Parents uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Normal Cervical Effacement in Term Labor. Am J Perinatol. 2019.

  3. Physiology, Cervical Dilation. StatPearls. 2023.

  4. Stages of Labor. StatPearls. 2023.

  5. Clinical Insights for Cervical Ripening and Labor Induction Using Prostaglandins. AJP Rep. 2018.

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