Prevalence and typing of HPV DNA in atypical squamous cells in pregnant women.

Objective: To determine the prevalence and typing of HPV DNA in pregnant women with a diagnosis of atypical squamous cells (ASC) and to assess whether pregnancy-related changes contribute to the diagnosis of ASC.

Study Design: HPV testing was performed on residual specimens from the ThinPrep Pap test (Cytyc Corp., Boxborough, Massachusetts, U.S.A.) in pregnant women diagnosed as ASC (study group, n = 105), low and high grade squamous intraepithelial lesion (LSIL and HSIL) (positive control, n = 33) and negative for epithelial cell abnormality (negative control, n = 20). All cases were reviewed by 2 cytopathologists to obtain consensus diagnoses using the Bethesda System 2001 criteria. The study group cases were further subcategorized into ASC of undetermined significance (ASCUS, n = 99) and ASC cannot exclude HSIL (ASC-H, n = 6). HPV testing was also performed on an ASC control group consisting of 68 consecutive ASC cases in nonpregnant women, matched by age.

Results: Mean patient age was 23.7 years for the study group and 25.6 years for the ASC control group. HPV DNA was detected in 88.6% of cases in the study group, including 87.9% of ASC-US and 100% of ASC-H cases. Of the HPV positive cases, 79.6%, 4.3%, 5.4% and 10.8% had high-risk, mixed high- and low-risk, low-risk and unknown HPV types, respectively. The most frequent HPV types detected were: types 52 (31.2%), 16 (15.1%), 39 (11.8%), 53 (10.8%), and 18 and 58 (9.7% each). Multiple viral types were detected in 43.0% of cases. The prevalence of HPV DNA in the positive and negative controls in pregnant women was 100% and 55%, respectively. HPV DNA was detected in 83.8% of the ASC control group.

Conclusion: Regardless of pregnancy-related changes, the prevalence of HPV DNA in pregnant women (88.6%) was similar to that found in ASC in nonpregnant women of the same reproductive-age group (83.8%), and the high-risk types accounted for the vast majority of cases (83.9%). These findings demonstrate that pregnancy-related changes do not contribute to the diagnosis of ASC in this subset of women. Furthermore, the high HPV DNA prevalence in reproductive-age women (< 40 years) suggests that HPV testing may have limited utility in effective management of these patients.