What Does the Cervix Do?

The cervix is a passageway into and out of the uterus. It widens during childbirth to allow for the passage of the baby. It also allows for the passage of menstrual fluid from the uterus, and sperm needs to travel through the cervix in order to reach the uterus.

Read on to find out more about how the cervix plays an important role in the female reproductive system.

Anatomy

Several key components contribute to cervical function. These areas of the cervix are often discussed during pregnancy, Pap smears, and colposcopy exams. It is important to become familiar with the anatomy of your cervix so you can understand possible changes that occur there and to understand what is involved in screening tests of the cervix.

Structure

• Endocervical canal: This is the potential space in the center of the tube of tissue that is the cervix. During a colposcopy, the healthcare provider may take a sample of cells in the endocervical canal. This is called an endocervical curettage (ECC).
• Ectocervix: This is the lower part of the cervix that protrudes into the vagina.
• Internal os: This part of the cervix is the opening into the uterus. During pregnancy and childbirth, you may hear your healthcare provider speak about the "os."
• External os: This is the opening of the ectocervix, which opens into the vagina.
• Transformation zone: This is also called the "TZ" for short. This is the area of the cervix where cervical dysplasia commonly occurs. The transformation zone may be discussed during a colposcopy exam.

Having regular Pap smears is imperative to detect any early changes in cervical cells that may lead to cervical cancer; however, you should know that the majority of abnormal Pap smears do not mean you have cancer.

Location

The cervix is the lower part of the uterus (womb). It makes up the passage between the vagina and uterus.

What Does the Cervix Do?

The cervix is the lower portion of the uterus. It is approximately 2 inches long, and it's tubular in shape. The cervix's three primary functions are:

• During menstruation, menstrual blood passes through the cervix and into the vagina, where it exits the body.
• The cervix produces cervical mucus, which varies throughout different parts of the menstrual cycle and during fertile times, making it easier for sperm to move through the cervix into the uterus.
  
• During childbirth, the cervix becomes thinner and wider. This creates an exit for the baby to pass through.

Associated Conditions

The cervix is vulnerable to several health conditions, such as chronic inflammation, polyps, dysplasia, and cancer.

Cervical Cancer

Cervical cancer is cancer that forms in the cells of the cervix. Most cervical cancer is related to infection by the human papillomavirus (HPV). HPV is a common sexually transmitted infection.

In the early stages, cervical cancer usually has no symptoms. In later stages, symptoms can include bleeding or spotting between periods, heavier than normal menstrual periods, pelvic pain or pain during sex, and abnormal discharge.

Cervical cancer is easiest to treat in the early stages, so it's important to have a regular Pap smear. A Pap smear can identify abnormal cervical changes long before they become cancerous.

Cervical Dysplasia

Cervical dysplasia is a condition in which abnormal cells grow on the surface of the cervix. It is not cancer, but it is considered a precancerous condition. Similar to cervical cancer, cervical dysplasia is often related to HPV infection. It can be detected during a Pap test and will usually resolve with treatment and follow-up care.

Cervical Polyps and Cysts

A cervical polyp is a small growth that appears on the surface of the cervix. Polyps are almost always benign, which means they are not cancerous. A small number of them, however, may become cancerous over time, which is why healthcare providers usually recommend removing them.

Nabothian cysts are benign, mucus-filled lesions that form when mucus-secreting glands are blocked by dead skin cells. They don't usually require treatment, though they can be drained by a healthcare provider.

Cervicitis

Cervicitis is an inflammation of the cervix. It is usually caused by a sexually transmitted infection such as chlamydia or gonorrhea. Occasionally, it can be related to using a cervical cap, an intrauterine device (IUD), or an allergy to a spermicide or latex condoms.

Pregnancy Complications

During pregnancy, the cervix helps keep the developing baby inside the uterus. Certain conditions of the cervix can cause problems during pregnancy, such as:

• Cervical insufficiency or incompetent cervix happens when your cervix opens too early. This can lead to miscarriage or premature birth.
  
• Short cervix is when your cervix isn't as long as it should be. This can also lead to premature birth.

Cervical Cancer Screening

Cervical cancer screening guidelines that were updated by the American College of Obstetricians and Gynecologists (ACOG) in April 2021 are:

The HPV vaccines do prevent cervical cancer and are an important way to protect yourself from getting it. However, people who have gotten the series of HPV vaccines still need to receive cervical cancer screening. The vaccine does not protect against all types of HPV that cause cervical cancer.

Summary

The cervix serves as a passageway in and out of the uterus. It widens during childbirth to allow the baby to pass through, and it lets menstrual blood leave the vagina. Sperm travels through the cervix to the uterus.

It is an important part of the female reproductive anatomy, and can also be associated with certain medical conditions. It's helpful to know the basics of reproductive anatomy in order to make informed decisions.

Regular Pap smears screen for cervical cancer and any abnormal cell changes. If you have questions about your cervical health or anatomy, talk with your healthcare provider.

Frequently Asked Questions

After ejaculation, it can take sperm only one minute or even less to reach the cervix. Studies on sperm migration show that sperm take two to 10 minutes to reach the fallopian tubes, where fertilization occurs.

Yes, it is safe to have a Pap smear while pregnant. The only potential risk is slight superficial bleeding caused by inserting or removing the speculum (an instrument used to widen the vagina).

People assigned male at birth do not. However, transgender men can have a cervix and may be at risk for cervical cancer.

Yes, you can. Place one or two clean fingers deeply into the vagina. It can feel a little like the tip of your nose. Depending on where you are in your cycle, it may be further back at certain times.

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.

1. American College of Obstetricians and Gynecologists. Colposcopy.
2. American College of Obstetricians and Gynecologists. Updated cervical cancer screening guidelines.
3. Custers M, Flierman A, Maas P, et al. Immobilisation versus immediate mobilisation after intrauterine insemination: randomised controlled trial. BMJ 2009;339:b4080. doi:10.1136/bmj.b4080
4. University of California, San Francisco (UCSF) Transgender Care. Screening for cervical cancer in transgender men.

By Jaime R. Herndon, MS, MPH
Herndon is a freelance health/medical writer with a graduate certificate in science writing from Johns Hopkins University.

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