A Pap smear is a cervical cancer screening test that’s a routine part of a gynecological exam. But just because it’s routine doesn’t mean we all know exactly what’s happening once we get up-close-and-personal with that speculum.
To find out everything there is to know about the Pap smear, we went straight to the expert: Dr. Kimberly Langdon, an OB-GYN with 19 years of clinical experience. She's researched and written extensively about women's health and is the inventor of six patent-pending medical devices. (Yeah, she’s a pro.)
Read on for the answers to these questions (and real talk on all things Pap):
- What happens during a Pap smear?
- What do you need to know about HPV?
- How often should you get a Pap smear?
- What do the results of a Pap smear mean?
What happens during a Pap smear?
During a Pap smear (which is usually done in conjunction with a pelvic exam), cells are collected from your cervix. First, a speculum is inserted into your vagina to hold the walls apart so that your healthcare provider can see your cervix. Then, a soft brush and a flat scraping device (known as a spatula) are used to remove a sample of cells from the cervix.
Why does your OB-GYN need to collect cells from your cervix? Because doing so can detect the early stages of cervical cancer. “More specifically, it detects abnormalities in the cells of the cervix, which are usually due to the Human Papillomavirus (HPV)," Dr. Langdon explains. Cervical cancer presents in the form of cervical dysplasia, or abnormal cells on the cervix. Depending on what the cells look like, dysplasia classifications can range from mild to severe. (More on these classifications later.)
Before the advent of the test, cervical cancer was one of the most common causes of death for women in the US. Then one doctor had a brilliant idea back in 1928: "Dr. George Papanicolaou suggested that cells scraped from the cervix and smeared onto a glass slide could be evaluated under a microscope to look for cancer cells," says Langdon.
The Papanicolaou test proved to be simple, low cost, and easy to interpret — and when it became a regular practice, it resulted in a dramatic decline (more than 70% since the 1950s) in incidences of cervical cancer. According to Dr. Langdon, "Pap smears have saved countless lives and are responsible for reducing the number of women from losing their fertility prematurely due to treatment for cervical cancer.”
In countries that lack cervical cancer screening, it’s unfortunately a major problem. 83% of cervical cancer-related deaths worldwide occur in developing countries -- and cervical cancer is the leading cause of cancer-related deaths among women in developing countries.
Let’s talk about HPV
HPV is a super common (and often asymptomatic) sexually transmitted infection (STI) that can lead to cervical cancer. If you're over age 30, your Pap test will be accompanied by a test for HPV. But not all forms of HPV can lead to cancer — two known specific types of HPV (Types 16 and 18) cause 80% of cervical cancer cases, and the HPV vaccine protects against both.
(By the way, another reason to never douche: Douching is also linked to an increased risk for HPV infection types 16 and 18.)
Routine Pap testing can alert your doctor to changes in cervical cells before cervical cancer actually develops, therefore allowing for intervention. “Until the prevention of HPV is widely embraced with vaccines," says Langdon, "Pap smears will continue to play an important role in cervical cancer screening."
How often should you get a Pap smear?
The American Society for Colposcopy and Cervical Pathology (ASCCP) has the following recommendations for Pap testing (even if you’ve already gotten the HPV vaccines):
- People with vaginas between the ages of 21 and 65 should get a Pap smear every three years.
- Between ages 30 and 65, Pap tests should be combined with HPV tests every five years.
- After the age of 65, if you’ve had “normal” Pap results for 10 years, screening can stop.
Those who have had a partial hysterectomy (the uterus is removed but the cervix remains in tact) will likely be advised to continue regular Pap smears. The same is true if the reason for the hysterectomy was to address a precancerous or cancerous condition.
There are also circumstances in which your doctor may recommend that you get a Pap smear more often:
- If you smoke or have a history of smoking.
- If you have HIV.
- If you've been diagnosed with cervical cancer in the past or you've had a Pap that's shown precancerous cells.
- If you were exposed to diethylstilbestrol (DES) (a synthetic estrogren prescribed to pregnant women between 1938-1971 to prevent miscarriage and premature birth). DES was revealed to cause a rare vaginal cancer known as clear cell adenocarcinoma in those who were exposed to it.
- If you have a compromised immune system because of an organ transplant, chemotherapy, or chronic corticosteroid use (steroids that address inflammation in the body).
Even if you became sexually active before the age of 21, a Pap isn't recommended earlier than that. According to the American College of Obstetricians and Gynecologists (ACOG), that’s because HPV is so common in teenagers and is likely to resolve itself without intervention. Treating a young person for HPV unnecessarily can also result in an increased risk of preterm birth later and can potentially damage the cervix.
According to Langdon: That doesn't mean that one shouldn't be tested at all for STIs if they’re younger than 21 and sexually active. "STI (gonorrhea, chlamydia, herpes) testing should be done based on risk factors and symptoms," she explains.
What do Pap smear results actually mean?
The cells collected during your Pap smear are analyzed in a lab to assess whether they're “normal” or “abnormal.” If only normal cells are discovered, the test results are considered "negative," and no follow-up is necessary. If your Pap test contains abnormal cells, those results are referred to as "positive," since cervical dysplasia is present, and you may need further testing.
Abnormal results in your Pap don’t necessarily mean you have cervical cancer. It might mean that you have one of the following:
- Atypical squamous cells of undetermined significance (ASCUS): The thin, flat cells that grow on the surface of the cervix appear atypical— but they don't necessarily indicate the presence of precancerous cells.
- Atypical squamous cell and cannot exclude a high grade squamous intraepithelial lesion (ASC-H): The thin flat cells that grow on the surface of the cervix appear atypical and may include a mixture of precancerous cells.
- Squamous intraepithelial lesion (SIL): These cells might be precancerous and your doctor will recommend additional testing. SIL cells are classified as low grade (LSIL, mild dysplasia) or high grade (HSIL, moderate to severe dysplasia).
- Atypical glandular cells: Glandular cells refer to the cells located within the cervical canal or the inside lining of the uterus. If these cells appear abnormal on a pap test, you will likely be told you need further tests in order to clarify.
- Squamous cell cancer or adenocarcinoma cells: These cells are the most abnormal and will likely be cancerous.
The follow-up for an abnormal Pap test in which moderate or severe dysplasia is present is a procedure known as a colposcopy, which is essentially a closer examination of the cervix with a high powered microscope and possibly a biopsy, or removal of abnormal tissue that’s then examined for further assessment.
Here’s how Langdon describes the procedure: “It’s like an extended pelvic exam. The gynecologist applies a dilute acid or lugols (an iodine solution) that visually highlights abnormal cells under a mobile microscope (called a colposcope).”
If an area is identified as abnormal, they will take a biopsy and send the tissue to the lab. If moderate or severe dysplasia is confirmed, a LEEP (Loop Electrosurgical Excision Procedure) is performed, where the abnormal section of the cervix will be removed.
In very rare situations where there’s evidence of persisting abnormal tissue or cancer, a cone biopsy (another excisional procedure) could be performed. The benefit of the excisional procedures is that they not only allow for further evaluation of the tissue, but can also “cure” the patient of the dysplasia. “Not every kind of cervical dysplasia merits a colposcopy. Since mild dysplasia usually clears up on its own, follow-up Pap smears are sufficient," Langdon explains.
If you ever have any questions or concerns about Pap smears, HPV, or cervical cancer, bring them to your doctor. (Writing them down in advance can help if you think you might not remember them once you're in that paper gown.)
And if you’re looking for more info about your reproductive health, Modern Fertility is always there to help. Take our test to check in with your hormones, learn more about your fertility, and start planning for the future.
This article was medically reviewed by Dr. Eva Marie Luo, an OB/GYN at Beth Israel Deaconess Medical Center and a Health Policy and Management Fellow at Harvard Medical Faculty Physicians, the physicians organization affiliated with the Beth Israel-Lahey Health System.