The Papanicolaou smear: Inadequate screening test for bacterial vaginosis during pregnancy

OBJECTIVE: Our purpose was to evaluate the ability of the Papanicolaou smear to identify bacterial vaginosis in comparison with the Amsel clinical criteria. STUDY DESIGN: We retrospectively identified 159 pregnant women screened for bacterial vaginosis with the Amsel criteria who had a contemporaneous Papanicolaou smear and negative results on screening for Chlamydia trachomatis and Neisseria gonorrhoeae. Bacterial vaginosis was identified in 45 women. We used the McNemar chi(2) test to determine discrepancies between the two screening methods for the detection of bacterial vaginosis. RESULTS: Compared with the Amsel criteria, the sensitivity and specificity of the Papanicolaou smear for yielding a diagnosis of bacterial vaginosis were 49% (95% confidence interval, 36%-64%) and 93% (95% confidence interval, 86%-97%), respectively, with a positive predictive value of 73% and a negative predictive value of 82%. The detection of bacterial vaginosis by Papanicolaou smear was significantly different from that by Amsel criteria (P = .01). CONCLUSION: The Papanicolaou smear is not a reliable screening test for bacterial vaginosis during pregnancy.