The Pap test is a routine screening procedure designed to detect changes in cervical cells. It finds potentially precancerous or cancerous processes, allowing for early treatment before symptoms develop. When results are abnormal, a common concern is whether hormonal birth control caused the cellular changes. Understanding the Pap test mechanics and the biological drivers of cervical abnormalities clarifies this relationship.
What an Abnormal Pap Test Result Means
An abnormal Pap test result indicates that cervical cells appear different from healthy cells when examined under a microscope. This finding requires further investigation but does not typically mean a cancer diagnosis. Findings are categorized using terminology that describes the degree of change observed.
The least severe finding is Atypical Squamous Cells of Undetermined Significance (ASC-US), meaning cells look slightly abnormal but the cause is unclear. More defined changes are Squamous Intraepithelial Lesions (SILs), divided into low-grade (LSIL) and high-grade (HSIL) categories. LSIL describes mildly abnormal cell changes, or mild dysplasia, which often clear up naturally.
HSIL indicates severely abnormal cells, or moderate to severe dysplasia. These changes are considered precancerous and are less likely to resolve spontaneously. If untreated, HSIL has a greater potential to develop into cervical cancer.
Hormonal Contraception and Cervical Cell Changes
Studies have explored the relationship between hormonal birth control and cervical cellular changes. Evidence suggests hormonal contraception, especially oral pills, is statistically associated with a small increased risk of cervical changes, but this is an association, not a direct cause. This link is primarily observed after consistent use for five or more years.
The proposed mechanism is that hormones may alter the cervical environment, making cells at the transformation zone more susceptible to infection. The transformation zone is the area where cell changes are most likely to occur. Hormone exposure can cause ectropion, exposing glandular cells from the inner canal on the outer surface of the cervix.
This exposure may make the cervix more vulnerable to the infectious agent driving these abnormalities. The association diminishes about ten years after stopping the medication. Birth control itself does not initiate cancerous change.
The Role of Human Papillomavirus
The primary cause of cellular abnormalities detected by an abnormal Pap test is a persistent infection with high-risk types of the human papillomavirus (HPV). HPV is a common sexually transmitted infection that most sexually active individuals contract. The majority of these infections are transient, cleared naturally by the immune system within one or two years.
If a high-risk strain of HPV, such as types 16 and 18, establishes a persistent infection, it can lead to changes in cervical cells. These two types are responsible for approximately 70% of cervical cancer cases worldwide. The virus integrates its genetic material into the cells, causing them to grow abnormally and leading to dysplasia.
The Pap test and the HPV test are often used together to screen for this process. An abnormal result indicates a persistent HPV infection driving cellular transformation. The HPV test clarifies if the abnormal cells are caused by a high-risk infection requiring monitoring or treatment.
Next Steps After an Abnormal Result
An abnormal Pap test result leads to a clinical management plan based on the severity of the cellular change and the presence of high-risk HPV. For mild changes (ASC-US or LSIL), the standard approach is watchful waiting, involving a repeat Pap test and HPV co-testing in six to twelve months. Many low-grade changes resolve spontaneously as the immune system clears the underlying HPV infection.
If the result shows HSIL or a persistent low-grade abnormality, a colposcopy is typically recommended. This procedure involves viewing the cervix through a magnifying instrument after an acetic acid solution is applied to highlight abnormal areas. During the colposcopy, the physician may take a biopsy (small tissue samples) for a definitive diagnosis.
If the biopsy confirms moderate to severe precancerous cells, a Loop Electrosurgical Excision Procedure (LEEP) may be performed to remove the abnormal tissue. Regular screening remains the most effective preventative strategy, including appropriate follow-up. HPV vaccination is highly effective at preventing the persistent infections that cause most cervical cellular abnormalities.