Papanicolaou smears in pregnancy. Positivity of exfoliated cells for human chorionic gonadotropin and human placental lactogen.

Trophoblastic cells are seen rarely in cervical exfoliative cytology during normal pregnancy but are thought to occur with increasing frequency in the clinical setting of threatened abortion. We performed a clinicopathologic and immunologic study to determine the significance of multinucleate syncytiotrophoblastic and cytotrophoblastic cells in cervicovaginal smears from 13 women identified by cytomorphologic screening during a six-year period. Control groups included 11 patients who subsequently had spontaneous abortions and 15 patients with uneventful pregnancies. Immunocytochemistry was performed using a cocktail of antihuman chorionic gonadotropin and antihuman placental lactogen antisera. Five of the 13 screen-positive cases, 1 of the 11 spontaneous abortion cases and 0 of the 15 normal pregnancies were positive on immunostaining. Clinical follow-up showed that none of the screen-positive pregnancies, including those also positive on immunostaining, ended in spontaneous abortion. Further, there was no significant difference in fetal weight or Apgar scores between the controls and the screen-positive group. The presence of trophoblastic cells on cervicovaginal smears during pregnancy is not a reliable indicator of impending abortion.