What is the cervix?

This cervix operating system It is part of the cervix, located in the lower part of the uterus. It connects the main part of the uterus to the vagina.

The cervix is ​​about 2 inches long, but can vary in length and width over a woman’s life.

This article discusses the anatomy of the cervix and the location of the cervical os. It also covers the role of the cervix in menstruation and pregnancy.

cervical anatomy

To describe the cervical os, it is helpful to first review the anatomy of the cervix.

The cervix contains:

  • ectocervix: the outside of the cervix that a doctor can see during a pelvic exam
  • External os: the opening in the center of the ectocervix
  • cervical canal: the passage that connects the vagina and uterus, also called the cervical canal
  • Internal opening: the opening from the cervix into the uterus
  • Transformation zone: the border that overlaps the external cervical and cervical canals

The role of the cervix in menstruation

Throughout the menstrual cycle, the cervix opens and closes with the phases of menstruation. Depending on the stage, the position of the cervix is ​​constantly changing, sometimes moving up and sometimes down.

During ovulation, the cervix will be high and positioned closer to the top of the vagina. This change in position will make it easier for the cervical os to open to allow sperm to enter.

The secretion of cervical mucus will further hold sperm by changing the vaginal environment from its natural acidic state to a more alkaline (alkaline) state. To better ensure sperm can enter the cervix, the mucus also becomes thinner and clearer.

During the non-fertile period of menstruation, the position of the cervix is ​​lowered and the cervix closes. Vaginal discharge becomes thicker and more acidic to protect against bacteria and other infectious agents.

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During ovulation, the opening of the cervix is ​​easier for sperm to enter. During the non-fertile phase of the menstrual cycle, the cervix is ​​closed and the cervix is ​​positioned lower.

The role of the cervix in pregnancy

After conception and the implantation of a fertilized egg in the uterus, the cervical opening changes. This change is in response to the stage of pregnancy and the growth of the developing fetus.

As the pregnancy progresses into the third trimester, the fetus begins to descend into the uterus in preparation for delivery. At this stage, the cervix provides stable support for your baby’s head. The baby is usually head down, towards the cervical canal.

As labor progresses, the cervix becomes softer and shorter, and the cervix begins to dilate or open. To accommodate the baby’s head during labor, the cervix must open more than four inches (10 cm) in diameter. In the process of widening, the cervix also becomes shorter and thinner, a phenomenon called disappearance.

During the erasure process, the internal and external operating systems are more tightly integrated. As the elimination and dilation progresses, the healthcare provider or midwife will use the extent of the cervical opening to help make treatment decisions.

During the first stage of labor, uterine contractions become strong and regular, and the cervix dilates to more than 2 inches (5 cm).

In the second stage, the cervix is ​​fully dilated by four inches (10 cm). This is when the mother begins to actively push for delivery through the birth canal.


During labor, the cervix becomes shorter and the inner and outer openings are brought closer together. The cervix is ​​dilated so that the baby can pass through the birth canal.

cervical self-examination

You can find the cervix during a simple self-exam. By inserting two (clean) fingers into the vagina, you can feel the cervix towards the back of the vaginal space. The cervix will feel round, and the cervix will feel like a small doughnut with a hole or indent in the center.

If you are planning to become pregnant, the quality and location of your cervix and os can help you determine if you are fertile:

  • When you ovulate, the cervix will open and relax, and the surrounding cervix will be high and soft, similar to pursed lips.
  • During non-fertile periods, the cervix is ​​low and firm, and the cervix closes.

closed cervix

In some cases, the cervical os closes completely. This is a condition called cervical stenosis. It is possible that the cervix is ​​closed at birth. It can also be the result of uterine surgery, endometriosis, scarring, cysts, or cervical cancer.

Symptoms may include periods of becoming more irregular or painful. A closed cervix can also lead to infertility because sperm cannot enter the uterus to fertilize an egg.

To diagnose a closed cervix, your gynecologist will need to perform a pelvic exam to see your cervix. If your OS seems narrow or unusual, they might try to probe through it. If they can’t, you may get a diagnosis of cervical stenosis.

Cervical closure does not always require treatment if you have no symptoms or are not planning to become pregnant.

However, if you are trying to get pregnant or have painful symptoms, your healthcare provider may recommend a cervical dilator. These are small devices placed inside your cervix that slowly expand over time, stretching your cervix.


A condition called cervical stenosis, or closure of the cervix, can lead to infertility because sperm cannot reach the egg. Your healthcare provider may recommend a cervical dilator if you are trying to get pregnant. These can slowly stretch and open up your cervix over time.


The cervical os is the opening of the cervix at both ends of the cervical canal. The outer opening is near the vagina, and the inner opening is near the uterus.

During your menstrual cycle, the cervix opens more easily during ovulation to allow sperm to enter. When you are pregnant, the cervix opens (dilates) during labor to allow the baby to pass through the birth canal.

A condition called cervical stenosis or closure of the cervix can cause dysmenorrhea. It can also cause infertility because sperm cannot reach the egg. To correct this, a cervical dilator can help slowly open the cervix over time.

Frequently Asked Questions

  • Where is the cervix during ovulation?

    No two bodies are the same. During ovulation, the cervix can be in a high, middle, or low position. Its location cannot be determined unless it is examined. In some cases it may be high enough to be unreachable. Remember, this is not an effective way to check if you are pregnant – for this, you will need a pregnancy test.

    understand more:

    How to check your cervix and cervical position

  • What does a soft cervix mean?

    When your cervix is ​​soft, it can mean you’re at your most fertile stage. This is because estrogen softens the cervical tissue. The feel of it on fertile is comparable to the softness of the lips.