Randomized Pilot Study Comparing Rates of Endocervical Cell Recovery between Conventional Pap Smears and Liquid-Based Cytology in a Pregnant Population.

OBJECTIVE.: To determine whether liquid-based cytology improves Pap smear adequacy, as defined by the presence of endocervical cells, compared with conventional cytology during pregnancy. MATERIALS AND METHODS.: A randomized pilot study was conducted between May 2001 and May 2002. Patients presenting for their first prenatal visit were randomized to receive either a conventional Pap smear or a liquid-based smear (ThinPrep). Rates of endocervical cell recovery and cytologic results were compared between the groups. RESULTS.: Eighty-one patients were enrolled in the study. There were no differences between the groups in age (p = .40), parity (p = .62), gestational age (p = .14), history of abnormal pap (p = .08), previous treatment of neoplasia (p = 1.00), and tobacco use (p = .67). Adequacy of the standard pap versus the liquid-based smear was not different between the two groups (90.5% vs 82.1%, respectively;p = .34). CONCLUSIONS.: The results of this pilot study show that rates of endocervical cell recovery in a pregnant population are not statistically different using conventional or liquid-based cytology. Further research is indicated to assess the utility of the more expensive ThinPrep technology in this population.