How are high false positive Pap (Papanicolaou) smear results managed during pregnancy?

Management of High False Positive Pap Smears During Pregnancy

Pregnant women with abnormal Pap smears should undergo colposcopy (without endocervical curettage or endometrial biopsy) to rule out high-grade lesions or invasive disease, with selective biopsy reserved only when high-grade lesions or cancer are suspected on colposcopic examination. 1, 2, 3

Initial Evaluation Approach

Colposcopy Indications

• All pregnant women with abnormal Pap results require colposcopic evaluation, regardless of the cytologic grade 2, 3
• The primary goal during pregnancy is to exclude invasive cancer, not to definitively treat preinvasive lesions 1
• Colposcopy should be performed by a clinician experienced in evaluating pregnant cervical changes, as pregnancy-related physiologic changes can mimic dysplasia 3, 4

Critical Modifications for Pregnancy

• Endocervical curettage is contraindicated in pregnant women 1, 2
• Endometrial biopsy is unacceptable during pregnancy 1
• Use a swab and Ayre's spatula for specimen collection; cytobrushes should be avoided or used with extreme caution to prevent disrupting the mucous plug 2, 3

Biopsy Decision-Making

When to Biopsy

• Perform colposcopically-directed biopsy only when colposcopy suggests high-grade lesions (CIN 2/3) or invasive cancer 3, 5
• For colposcopic findings consistent with low-grade changes or minor abnormalities, biopsy can be deferred with repeat colposcopy during pregnancy or postpartum 3, 5

Common Pitfall to Avoid

Research demonstrates that 83.6% of pregnant patients with colposcopic impressions of CIN 2 or greater did not undergo biopsy, and this conservative approach led to delayed diagnosis of invasive cancer in some cases 5. While pregnancy does warrant a higher threshold for biopsy, do not defer biopsy when high-grade disease or cancer is suspected colposcopically 5.

Understanding False Positives in Pregnancy

Physiologic Changes That Mimic Dysplasia

• Severe inflammation with reactive squamous cellular changes is extremely common during pregnancy and frequently causes false-positive cytology 3
• Pregnancy-related decidual changes, Arias-Stella reaction, and increased vascularity can be misinterpreted as glandular atypia 4
• These benign changes explain why many abnormal Pap smears in pregnancy do not correlate with significant histologic findings 6, 7

When to Suspect True Pathology

• Atypical glandular cells (AGC) warrant particular concern, as they can be associated with adenocarcinoma in situ even during pregnancy 1, 4
• High-grade squamous intraepithelial lesions (HSIL) require immediate colposcopic evaluation with low threshold for biopsy 3

Follow-Up Strategy

During Pregnancy

• For low-grade abnormalities without concerning colposcopic findings: repeat colposcopy can be performed later in pregnancy or deferred to postpartum 3, 5
• For high-grade lesions confirmed on biopsy: serial colposcopy every 8-12 weeks during pregnancy to monitor for progression 1
• Definitive treatment should be deferred until postpartum unless invasive cancer is diagnosed 1, 3

Postpartum Management

• All pregnant women with abnormal Pap smears require postpartum follow-up at 6-12 weeks after delivery 3, 5
• Research shows that 42% of patients fail to return for postpartum follow-up, and invasive cancers have been diagnosed in women who did not undergo adequate surveillance 5
• Aggressive patient education and tracking systems are essential to ensure postpartum compliance 5

Special Considerations for Atypical Glandular Cells (AGC)

• AGC during pregnancy requires the same initial workup as non-pregnant women (colposcopy with endocervical sampling), except endocervical curettage and endometrial biopsy are contraindicated 1
• Endocervical sampling with a cytobrush or swab is acceptable if performed carefully 1, 4
• AGC has higher association with significant pathology (adenocarcinoma in situ, invasive adenocarcinoma) and warrants lower threshold for biopsy even during pregnancy 1, 4

Risk Stratification

Higher Risk Patients Requiring Closer Surveillance

• Young age at first intercourse (coitarche) 6
• Multiple sexual partners 6
• More than 25 years of sexual activity 6
• HIV-positive status: these patients require colposcopy and directed biopsy for any abnormality (ASCUS or higher) 3

Lower Risk Scenarios

• ASCUS or LSIL with satisfactory colposcopy showing only minor changes can be followed conservatively 3
• Prevalence of true premalignant lesions in pregnancy ranges from 0.8% to 6%, with most abnormalities representing benign reactive changes 6, 7