Dysplasia during pregnancy: a cytologic follow-up study.

To clarify the characteristics of dysplasia in the pregnant state, 525 of 703 dysplasias in pregnant women recorded in the laboratory computer at the University of Chicago Lying-in Hospital during a ten-year period were selected for study through medical records. These materials were basically diagnosed by cytologic techniques. The regression rates of moderate and marked dysplasia within a six-month period after delivery seemed to be much higher than those of dysplasia in the general population. The progression rates of dysplasia to carcinoma in situ during pregnancy and after delivery were almost the same as those of dysplasia in the nonpregnant state, whereas the progression rate of dysplasia to invasive carcinoma after delivery (0.4%) was almost half that in the nonpregnant state (1%). With reference to the latent period during which dysplasia progressed to malignancy, dysplastic lesions during pregnancy, as compared to those in nongravid women, had a higher potential for progression. The number of dysplastic cells decreased with the course of pregnancy. The rates of metaplastic and keratinizing types of dysplasia were remarkably higher than those in the general population, and the rates of those types of dysplasias increased with the course of pregnancy.