During a 3 year period, 35 pregnant woman with grade III or IV cytological changes found at pregnancy control were followed during pregnancy and up to 4 years after delivery. These 35 patients constitute 0.35% of all the pregnant women admitted for antepartum consultation. Complete regression of dysplasia was seen in one third of the patients. The patients were followed with colposcopy and sometimes punch biopsy and the decision regarding final treatment was postponed until 8 weeks after delivery. No invasive lesion was found, and no recurrences or invasive lesions were found at follow up. It is concluded that cytology and colposcopy with punch biopsy on suspicion of early invasion is an adequate control procedure during the pregnancy at intervals of 2-3 months.