[Cytodiagnosis and premature birth in light of the Bethesda system]

1. Evaluation of cytological cervico-vaginal smears by the Bethesda system enlisted cytodiagnostics among important laboratory methods which can be used also in risk pregnancies. 2. Vaginal cytology makes it possible to test at the same time the hormonal situation during pregnancy, which reflects the placental function, and to evaluate also the vaginal biocenosis. 3. The authors provided evidence that the large number of superficial cells on the cytological smear (more than 10%) is associated with low oestriol and pregnandiol levels which are warning signs of the approaching termination of pregnancy. 4. By the action of microorganisms on the vaginal epithelium typical morphological changes develop in the cell nucleus and in the cytoplasm. By polychromatic staining also the causal agents of inflammations and infections threatening the mother and foetus are apparent. 5. The authors assume that cytological examination and evaluation according to the Bethesda system should be included in the complex of antenatal examinations also in women without clinical symptoms of premature delivery or without signs of vaginal infection.