Dilation is the process by which the cervix opens during childbirth. The cervix is the lower part of the uterus, where it opens to the vagina.
During labor, contractions cause the cervix to change from being closed to fully dilated or open to 10 centimeters. Once that happens, it’s time to begin pushing.
Read on to learn more about dilation during pregnancy, including how dilation is measured, symptoms, phases, and more.
How Dilation Is Measured
Dilation is measured in centimeters. For most of the pregnancy, the cervix is closed. However, as labor approaches, the cervix opens as it begins to prepare for childbirth. Some people become 1-2 centimeters dilated before they start active labor, while others start active labor without being dilated at all.
When your cervix is fully dilated, the opening will measure 10 centimeters or about 3.9-inches. That’s the same diameter as a large bagel or cantaloupe cut in half. It’s large enough for the baby’s head to pass through.
When you are in labor, your healthcare provider will check your dilation through a cervical exam. During this exam, they will insert their gloved finger into your vagina to check how wide the cervix has dilated.
Most people do not find these exams painful, although they can be uncomfortable. Unless there are complications, your healthcare provider will likely check you when you are admitted and before you begin pushing. Checking dilation too frequently can introduce bacteria to the vagina.
Effacement vs. Dilation
In order to birth a baby, your cervix must be thin and open. Effacement refers to how thin the cervix is, which is measured as a percentage. In order to give birth, your cervix must be 100% effaced. This often happens before labor, and you may notice signs, like losing your mucus plug or experiencing more discharge. Once the cervix is effaced, dilation can occur.
Dilation is caused by contractions. These contractions cause the muscles in your abdomen to become very tight, then relax. At first, these contractions may be mild and barely noticeable. As labor progresses, you’ll experience more intense contractions. You’ll also notice other symptoms of active labor, including:
- Strong, regular contractions that cause pain in your abdomen and back.
- Increased discharge, which may be bloody, brown, or contains mucus.
- Water breaking or when the amniotic sac ruptures. There may be a gush or a trickle of amniotic fluid, or it may not happen until late in labor.
It’s normal for contractions to start and stop before true labor sets in. Unfortunately, that can make actual labor hard to spot. Once your contractions last for 30 to 70 seconds and are five to 10 minutes apart, it’s time to call your healthcare provider.
Phases of Dilation
Healthcare providers divide labor into three stages:
- First stage: During this stage you experience regular contractions, increasing in intensity. All dilation takes place in the first stage of labor. The first stage lasts for many hours.
- Second stage: The second stage is when you are actively pushing your baby out. It lasts from minutes to three hours. This stage begins when your cervix is fully dilated.
- Third stage: The third stage is the delivery of the placenta, which often takes about 30 minutes.
It can be helpful to break the first stage down since this is the longest part of labor. The two phases of stage one are:
- Latent phase: Also known as early labor, this is when your cervix is effacing and starting to dilate. Contractions are regular, starting mild and increasing in intensity. During this stage, dilation will move from 0 to 3-4 centimeters.
- Active phase: When your cervix has dilated to 4 centimeters, your contractions will likely become more intense. They’ll last longer and come closer together, which will help you dilate to a full 10 centimeters.
While dilation is a natural process, it doesn’t always go seamlessly. Some people experience complications with dilation. If your cervix cannot fully dilate, your healthcare provider may suggest a cesarean delivery (C-section).
Sometimes, your healthcare provider might decide that inducing labor, or artificially jump-starting it, is what is healthiest for parent and baby. This may happen if:
- You’re more than two weeks past your due date
- Your water broke, but labor didn’t start
- You have health concerns, such as high blood pressure or low amniotic fluid
If you need to be induced, your healthcare provider will likely use various means to encourage dilation and the start of labor. These may include:
- Using the hormone prostaglandin causes the cervix to soften and efface. Prostaglandin can be taken orally or inserted into the vagina.
- Using the hormone oxytocin (in the form of the medication Pitocin) to induce contractions, which cause dilation.
- Using a Foley Bulb induction, where a catheter is inserted into the cervix. The catheter is slowly injected with saline solution, putting pressure on the cervix and causing it to open.
When Dilation Happens Too Early
If labor starts before 37 weeks, it is considered preterm labor. A fetus born too early faces risks, including death and serious illness. If you’re experiencing early dilation, your healthcare provider might suggest treatments to try and reduce your risk of preterm labor. They may also provide steroids that will help your baby’s lungs develop in case they are born early.
The treatments for preterm labor include:
- Progesterone: When given as a shot or inserted into the vagina, this hormone can reduce the risk for preterm labor.
- Cerclage: If your cervix begins to dilate very early, your healthcare provider may use stitches to sew the opening closed. This is known as cervical cerclage. The stitches are removed at 36 weeks gestation, allowing for normal dilation during labor.
Your healthcare provider may also recommend bed rest or reduced activity to help prevent further dilation.
What Is Cervical Insufficiency?
Cervical insufficiency is a condition that causes the cervix to efface and dilate too early. It’s the cause of about 1% of preterm births.
Dilation is when the cervix opens during labor as your body is getting ready for childbirth. Contractions of the uterus cause the cervix to dilate. When the cervix measures 10 centimeters, you can begin pushing. If your cervix does not fully dilate, your healthcare provider may try different methods to induce dilation or recommend a C-section. Other times, the cervix may dilate too early, which may lead to preterm labor. Your healthcare provider will try different treatments to prevent further dilation if labor starts before 37 weeks.
A Word From Verywell
Anticipating labor can be both exciting and scary. Knowing what to expect can help you feel more in control, but remember: there's no way to know what will happen when it's time to give birth. Surrounding yourself with trusted healthcare providers and loved ones can help you feel confident when the time comes.
Frequently Asked Questions
When does your healthcare provider start checking for dilation in pregnancy?
Some healthcare providers will check dilation as you approach your due date, but this isn't an indication of how far or close labor is. Most people will have a cervical check when they get to the hospital and before they start pushing.
How long does dilation take during labor?
Dilation can take hours or days. It is highly individualized. As long as your body is making steady progress your healthcare provider will likely allow your body to dilate until you reach 10 centimeters.
Verywell Health 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.
John Hopkins. Labor.
American College of Obstetricians and Gynecologists.How to tell when labor begins.
My Health Alberta. Cervical effacement and dilation.
March of Dimes. Contractions and signs of labor.
Nemours Kids Health. Inducing labor.
Nemours Kids Health. Treatments to prevent premature birth.
Yale Medicine. Cervical insufficiency.
By Kelly Burch
Kelly Burch is has written about health topics for more than a decade. Her writing has appeared in The Washington Post, The Chicago Tribune, and more.
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Dilatation means that the cervix opens. As labour nears, the cervix may start to thin or stretch (efface) and open (dilate). This prepares the cervix for the baby to pass through the birth canal (vagina). How fast the cervix thins and opens varies for each woman.What is normal dilation? ›
The cervix must be 100% effaced and 10 cm dilated before a vaginal delivery. The first stage of labor and birth occurs when you begin to feel persistent contractions.What is a good dilation? ›
A woman is considered to be in the active stage of labor once the cervix dilates to around 5 to 6 cm and contractions begin to get longer, stronger, and closer together.What is your dilation? ›
Dilation is when your cervix opens (dilates) and the opening is measured in centimeters. During the first stage of labor, the cervix opens and thins out (effaces) to allow the baby to move into the birth canal.How much do you dilate when pregnant? ›
The cervix must be 100% effaced and 10 cm dilated before a vaginal delivery.When does dilation start? ›
The American College of Obstetricians and Gynecologists (ACOG) explains that the cervix can begin dilating a few days before labor truly begins.How long does it take to dilate from 1 to 10? ›
When your baby is ready to begin the journey through the birth canal, your cervix dilates from fully closed to 10 centimeters. This process can take hours, days, or even weeks. But once you hit active labor – about 6 cm dilated – it's usually just a matter of hours before you reach full dilation.How can I speed up dilation? ›
Getting up and moving around may help speed dilation by increasing blood flow. Walking around the room, doing simple movements in bed or chair, or even changing positions may encourage dilation. This is because the weight of the baby applies pressure to the cervix.How dilated should I be at 38 weeks? ›
It may be hard to talk or move easily. At this point, your cervix will be dilated 3 to 10 centimeters. (Dilating one centimeter an hour is textbook, but like in early labor, it's different for everyone.) If you're opting for an epidural, the time is…now!What helps your cervix dilate? ›
- HERBAL SUPPLEMENTS.
- CASTOR OIL, HOT BATHS, AND ENEMAS.
- SEXUAL INTERCOURSE.
- BREAST STIMULATION.
- ACUPUNCTURE/TRANSCUTANEOUS NERVE STIMULATION.
- MECHANICAL MODALITIES.
- SURGICAL METHODS.
- Stripping of the Membranes.
Try to insert the tips of your fingers into your cervix. If one fingertip fits through your cervix, you're considered one centimeter dilated. If two fit, you're two centimeters dilated. If there's additional space in the opening, try to estimate how many fingertips would fit to determine dilation.How many cm dilated do you have to be to go to the hospital? ›
If you're more than 4 cm dilated: You'll be admitted to the hospital to continue your labor and delivery.Can you feel how dilated you are? ›
#3: Cramping and backache
If they occur low down, just above your pubic bone, this can be a sign your cervix is dilating. It might feel something like the cramping ache you have just before, or at the start of your period. You might also feel a dull ache in the lower part of your back, which comes at regular intervals.
Theoretically, the unequal walking pattern created by the curb causes the pelvis to open and allows the baby's head to descend. When the baby's head is deeper into the pelvis, there is more pressure on the cervix, causing dilation and effacement. This uneven walk should be done for about 10 minutes.How long after dilation does baby come? ›
The time between dilating to 1 cm and giving birth varies from woman to woman. One woman may go from having a closed cervix to giving birth in a matter of hours, while another is 1–2 cm dilated for days or weeks. Some women do not experience any dilation until they go into active labor.What are the three stages of dilation? ›
The dilation (opening) stage is the longest, while the expulsion (pushing out) stage lasts 30-60 minutes, and the placental stage takes from a few minutes to up to 60 minutes. Various factors influence how long it takes to give birth: Whether you've given birth before or not.
Your cervix needs to open about 10cm for your baby to pass through it. This is what's called being fully dilated. In a 1st labour, the time from the start of established labour to being fully dilated is usually 8 to 12 hours. It's often quicker (around 5 hours), in a 2nd or 3rd pregnancy.Does your water have to break to be dilated? ›
Rupture Of Membranes: Your Water Breaks
The so-called "rupturing of the membranes" can happen at the very start of labor or during the first stage of labor. Usually the doctor, midwife, or nurse will break your water before you become completely dilated, if it hasn't broken by then.
A fully dilated cervix is 10 centimeters open. This means that when your cervix is measured with two fingers, they can be stretched 10 centimeters across. When you're fully dilated, it's time to push and have a baby.What causes your body to not dilate? ›
the baby has a large head. the baby is in a difficult position. contractions aren't strong enough and your cervix doesn't open (dilate) pelvis is too small to fit your baby through.
When we sit on the toilet, we naturally let our pelvic floor relax. When we allow these muscles to soften, all of the hard work our uterus is doing pays off by allowing our cervix to thin, dilate, and get us closer to meeting our baby.How can I open my cervix naturally? ›
Some herbal remedies such as red raspberry leaf tea, black and blue cohosh, and evening primrose oil have been known to help ripen a cervix and prepare the body for labor. But before trying an herbal remedy, talk to your doctor or midwife to ensure it is safe for you.How much should your cervix be dilated at 39 weeks? ›
This cervical ripening can begin days or even weeks before delivery. You might notice this process beginning with an increase in vaginal discharge or even losing your mucus plug. If you're delivering vaginally, once your cervix opens to the magic number—10 centimeters—you're ready to push and deliver.What foods make your cervix dilate? ›
- Spicy food. Perhaps one of the most well-known theories is that eating spicy food can bring on labor. ...
- Prunes. ...
- Walking. ...
- Sex. ...
- Dates. ...
- Red raspberry leaf tea. ...
- Castor oil. ...
- Evening primrose oil.
massage around the neck of your womb if it is soft but closed — this 'stretch' can stimulate your body to release prostaglandins, which encourage the cervix to open.Is it painful when cervix dilate? ›
As cervical dilation increased, there were significant increases in self-reported pain and observed pain on all the cited measures. Pain was characterized as 'discomforting' during early dilation and as 'distressing, horrible, excruciating' as dilation progressed.What does it feel like when baby drops? ›
Once your baby drops, you might notice a lot of increased pressure in your pelvis. This may be a time when you develop a significant pregnancy “waddle” as you adjust. This is probably the same feeling as walking around with what feels like a bowling ball between your legs.When do you lose your mucus plug? ›
Most people don't lose their mucus plug until after 37 weeks of pregnancy. In some cases, losing the mucus plug happens days or weeks before your baby's due date. Some people don't lose it until they're in labor.What are the 5 signs that you are in labor? ›
- contractions or tightenings.
- a "show", when the plug of mucus from your cervix (entrance to your womb, or uterus) comes away.
- an urge to go to the toilet, which is caused by your baby's head pressing on your bowel.
- your waters breaking.
Phase 2 begins once the cervix is 3 or 4 cm dilated. It is called active labor. The contractions are stronger than phase 1 and occur more often. It is important to time your contractions.
As your baby's birthday gets close, your cervix begins to dilate, or open up. Dilation is checked during a pelvic exam. Typically, if you're four centimeters dilated, you're in the active stage of labor. If you're fully dilated, you're ready to start pushing.How do you know labor is days away? ›
A few days before labor, you may notice looser, more relaxed joints in your pelvis and lower back. You might also experience an unexpected side effect of relaxin — diarrhea. This can happen as the muscles around your rectum relax.How do you know if you are dilating? ›
- As your baby's birthday gets close, your cervix begins to dilate, or open up.
- Dilation is checked during a pelvic exam.
- It is measured in centimeters, from 0 (no dilation) to 10 (full dilation)
- Typically, if you're four centimeters dilated, you're in the active stage of labor.
Phase 2 begins once the cervix is 3 or 4 cm dilated. It is called active labor. The contractions are stronger than phase 1 and occur more often. It is important to time your contractions.How do I know if I'm dilated? ›
Dilation is checked during a pelvic exam and measured in centimeters (cm), from 0 cm (no dilation) to 10 cm (fully dilated). Typically, if you're 4 cm dilated, you're in the active stage of labor; if you're fully dilated, you're ready to start pushing.How can I tell how dilated I am at home? ›
Check for dilation.
Try to insert the tips of your fingers into your cervix. If one fingertip fits through your cervix, you're considered one centimeter dilated. If two fit, you're two centimeters dilated. If there's additional space in the opening, try to estimate how many fingertips would fit to determine dilation.
Can you feel your cervix dilating? As your cervix starts to thin and soften, you may or may not notice twinges and sensations in that area of your pelvis. This can be as much you trying to convince yourself something is happening though!Will the doctor send you home at 4 cm dilated? ›
If you're less than 4 cm dilated: You might be sent home because your labor isn't active enough for hospital admission.How many cm dilated go to hospital? ›
Based on the timing of your contractions and other signs, your doctor or midwife will tell you to head to the hospital for active labor. This phase typically lasts from three to five hours and continues from the time your cervix is 3 cm until it is dilated to 7 cm. True labor produces signs you don't want to ignore.How many cm dilated do you need to be to be admitted? ›
Generally, doctors are looking to admit individuals who have dilated to 3-4cm with consistent contractions that are five minutes apart and about a minute long. However, there are other reasons why someone who does not meet those parameters to be admitted.
As pregnancy progresses and you prepare to give birth, the cervix gradually softens, decreases in length (effaces) and opens (dilates). If you have an incompetent cervix, your cervix might begin to open too soon — causing you to give birth too early.When do doctors check for dilation? ›
We will start doing cervical exams to see if the cervix is starting to dilate. If you are scheduling an induction, we will also schedule that around this time. When your physician checks you, several things are being assessed: Cervical dilation—how open is the cervix?