What Is the Cervix?
The cervix is the lower part of the uterus that opens into the vagina; this is called the endocervical canal. The cervix is narrow but has a small opening called the os, which allows menstrual blood to flow. During pregnancy, the cervix normally remains closed to keep the fetus inside of the uterus until it is time for birth. When labor begins, the cervix gradually opens -- or dilates -- and thins -- or effaces -- in order to allow the fetus to exit the uterus.
Typical Appearance of the Cervix
The closed cervix looks like a doughnut with either a slit or a dot at the center of it. If you have delivered a child vaginally before, the os or the opening in the cervix will look like a slit.
The cervix also goes through changes related to hormones and ovulation. The cervix creates mucus, which can indicate what stage of your menstrual cycle you are in. After menstruation, the cervix is dry and somewhat lumpy. There is very little mucus at that time. Pre-ovulation, the cervical mucus is white and sticky; gradually, the mucus changes to cloudy and stretchier.
During ovulation, this mucus becomes clear and stretchy and resembles raw egg whites. Your cervical position may be higher in the vagina and the cervix itself may feel wet. You can monitor your cervical mucus throughout your cycle by testing its consistency. Many women use these changes as predictors and signs of fertility when trying to get pregnant; using this method can pinpoint ovulation.
After ovulation, the cervix starts to return to its dry and closed state.
What Does a Dilated Cervix Look Like?
When you become pregnant, the cervix may appear pinker because of the increased blood flow. The cervix is also tightly closed to prevent a miscarriage and is plugged by a mucus plug, which can prevent infection. During delivery, the cervix gradually becomes dilated and effaced to allow the fetus passage through the birth canal.
- Effacement: The pressure of the head coming into the birth canal causes the cervix to compress and then thin out. As the cervix thins, it pulls into the lower part of the uterine wall. Effacement is expressed by a percentage with the goal being 100 percent.
- Dilation: The contractions of the uterus cause the opening or dilation of the cervix; the pressure of the fetus's head -- with the contractions -- can force the cervix open to 10 centimeters.
The cervix opens more with each progressive stage of labor:
- Latent phase of labor: 0-3 centimeters
- Active labor: 4-7 centimeters
- Transition phase: 8-10 centimeters
With each stage of labor, the opening in the center of the cervix gets larger and the rim gets thinner; some have decribed this appearance like a sweater being pulled over a head. Dilation is complete when the cervix is dilated to 10 centimeters.
Effacement and dilation occur during the same time frame. When the cervix is completely effaced and dilated, it should be difficult to see and should look like a rim around the head of the fetus. At this point, the answer to the question "What does a dilated cervix look like?" should be that you should not be able to tell where it is; it has retracted into the uterus.
Checking the Cervix
Your nurse, physician, doula, or midwife will check your cervix during labor to determine the number of centimeters that you are dilated and the percentage of your cervical effacement. It is best to have the same people checking as much as possible; these measurements are often a percentage and not absolute numbers. Your male doctor may get a slightly different measurement that a petite female nurse because their hand sizes will be different.
Descriptions of "what does a dilated cervix look like?" may not give you a clear image. There are slideshows online that women and doctors have taken during all stages of labor; these videos can let you see a dilated cerivx at various stages. You can also video your own delivery and discuss getting these images with your physician.