Comparative study of cytology and punch biopsy in cervical intraepithelial neoplasia during pregnancy. A preliminary report.

To elucidate the accuracy of cytology in diagnosing cervical intraepithelial neoplasia (CIN) during pregnancy, cytologic screenings for uterine cervical cancer in pregnant women were reviewed for a five-year period. Of the 967 pregnant women screened, abnormal cytologic findings were recorded for 15 (1.6%). Only nine of these were subsequently examined by colposcopy and punch biopsy, which demonstrated CIN in all cases, for an incidence of documented CIN during pregnancy of 0.93%. Including two referral cases also examined by colposcopy and biopsy, cytology and histology agreed on the degree of CIN in four cases and disagreed by one degree in four cases, by two degrees in two cases and by three degrees (mild dysplasia versus carcinoma in situ) in one case. Review of the specimens from these cases did not readily explain the poor concordance between cytology and punch biopsy; some findings suggest that overestimation of the punch biopsy sample may be the explanation.