Cervical intraepithelial neoplasia (CIN) is a condition that causes abnormal cell growth (neoplasia) on the outer lining of your cervix known as the intraepithelial tissue. CIN is also sometimes also called cervical dysplasia.

While it requires some medical intervention, CIN doesn’t usually cause symptoms. There are complications that can occur, though, if these noncancerous cells go undetected and are left with the opportunity to multiply or mutate (change). This is why getting routine Pap smears is such an important part of preventive healthcare. Only a Pap smear can see the signs of CIN.

Signs and Symptoms

CIN is usually thought of as asymptomatic (without symptoms). However, there is an association between CIN and bleeding after penetrative sex (known as postcoital bleeding, or PCB).

A 2019 limited-sample study conducted in Israel suggests that bleeding after sex may be a sign of the following:

  • Infection such as HPV (human papillomavirus) infection CINCervical cancer

Diagnosis was through colposcopy, a simple procedure used to examine the cervix.

Signs of CIN From a Pap Smear

Your Pap smear, or Pap test, results will determine whether or not you have cell abnormalities or lesions on your cervix known as squamous intraepithelial lesions, or SILs. In many cases, these lesions will clear away on their own as your body’s natural defenses destroy them. Other times, the cells may have spread already so further medical intervention may be necessary. 

Pap Smear

A brief, routine procedure where cells from the cervix are removed with a small brush or spatula. These cells are then examined under a microscope to check for cervical cancer or cell changes that may lead to cervical cancer.

The cell sample findings from your Pap smear are categorized based on how far they have spread across your outer cervical lining, known as intraepithelial tissue, and based on your risk factors for human papillomavirus or HPV (the sexually transmitted infection that causes CIN) or cervical cancer.

The signs will be categorized as follows:

  • Low-grade SIL (LSIL)High-grade SIL (HSIL)Possibility of cancerAtypical glandular cells (AGUS)

Another way of categorizing CIN based on the same information collected from your Pap is by numbered grades (1–3) rather than scaled grades (low–high). Your doctor may use terms from either categorization method, so if you’re not sure what they’re referring to, simply ask for some clarification.

The three grade levels include:​​

  • Low-grade neoplasia (CIN 1) involves about one-third of the thickness of the epithelium.CIN 2 refers to abnormal changes in about one-third to two-thirds of the epithelial layer.CIN 3 (the most severe form) affects more than two-thirds of the epithelium.

Complications

Most of the time there are no complications associated with CIN since it doesn’t often progress to cervical cancer. Your immune system may fight the infection and make it resolve. If for some reason it doesn’t, you can rest assured that there are many intervention strategies and treatments to fight it.

What Is an Abnormal Pap Test Result?

According to the National Cancer Institute, an abnormal finding (also called a positive result) doesn’t automatically mean you have cervical cancer. Still, following through with doctor recommendations—like getting a colposcopy and a biopsy—is necessary. Your healthcare provider can determine the total level of risk in your personal situation and the next appropriate steps.

Common options to reduce complications include removing the cells or destroying them so healthy cells can replace them. These treatments can even be used in later disease stages, in which the diseased cells have spread.

People with weakened immune systems (including those with human immunodeficiency virus (HIV) and AIDS are at greater risk of experiencing complications because they may be less able to fight off HPV. They may also be more likely to develop health problems from HPV.

Most Common Complications

The biggest concern and complication associated with CIN is HPV and cervical cancer.

When to See a Doctor

If you experience postcoital bleeding, whether it’s once in a while or all the time after engaging in penetrative sexual activity, see your doctor to begin the process of getting an accurate diagnosis.

You should also be have regular Pap tests. Here’s what the National Cancer Institute’s 2020 Guidelines recommend based on your age group.

While your doctor can test you for HPV in their office, there are also at-home HPV tests available. If you have HPV, it is recommended that you see a doctor to discuss treatment options.

A Word From Verywell

Chances are you’re not going to notice any signs or symptoms of CIN. This is why it’s important to get tested in accordance with the guidelines listed above. This way, if you ever do have CIN, your healthcare provider can catch it in its early stages and determine next steps.

Remember, if you have questions, you can always contact your healthcare provider or women’s clinic to discuss whether or not it’s time for you to get a Pap or HPV test.

Frequently Asked Questions

  • How is CIN diagnosed?
  • CIN is diagnosed through a Pap test at a doctor’s office and an HPV test that can be performed at the same time or at home.
  • Does CIN 3 have symptoms?
  • Symptoms are rare in CIN 1, CIN 2, and CIN 3. Most people with a cervix will not experience symptoms with CIN, which is why cervical screening is so necessary. Postcoital bleeding is one sign of CIN.
  • How serious is CIN 3?
  • CIN 3 is not cancer but should still be treated with the seriousness of any other medical condition as it has the potential to spread and turn into cancer if left untreated.

CIN is diagnosed through a Pap test at a doctor’s office and an HPV test that can be performed at the same time or at home.

Symptoms are rare in CIN 1, CIN 2, and CIN 3. Most people with a cervix will not experience symptoms with CIN, which is why cervical screening is so necessary. Postcoital bleeding is one sign of CIN.

CIN 3 is not cancer but should still be treated with the seriousness of any other medical condition as it has the potential to spread and turn into cancer if left untreated.

  • Cohen O, Schejter E, Agizim R, Schonman R, Chodick G, Fishman A, Klement AH. Postcoital bleeding is a predictor for cervical dysplasia. PLOS ONE. 14(5):e0217396. doi:10.1371/journal.pone.0217396
  • National Cancer Institute. Cervical cancer prevention (pdq®)–patient version.
  • Cleveland Clinic. Cervical intraepithelial neoplasia (CIN).
  • Centers for Disease Control and Prevention. How Many Cancers Are Linked with HPV Each Year?.
  • Centers for Disease Control and Prevention. STD facts human papillomavirus.
  • National Cancer Institute. Acs’s updated cervical cancer screening guidelines explained.

By Michelle Pugle

Michelle Pugle, BA, MA, is an expert health writer with nearly a decade of contributing accurate and accessible health news and information to authority websites and print magazines. Her work focuses on lifestyle management, chronic illness, and mental health. Michelle is the author of Ana, Mia & Me: A Memoir From an Anorexic Teen Mind.