Commentary

A few years ago, a senior resident challenged me to produce evidence that vaginal lubricant interfered with cervical cytology results. My literature searches yielded no reports, even though I had been taught not to use lubricant when obtaining a Pap smear because it could affect the quality of the smear. At last, 2 studies have addressed this clinical question. Amies et al randomised 5 family planning clinics to use vaginal lubricant or tap water on the speculum, and found no difference in the rate of unsatisfactory smears. This study had more than 80% power to detect a doubling of the rate of unsatisfactory smears (p<0.05), so an increase in the rate of unsatisfactory smears would not have been missed. Harer et al randomised 182 women at a single health clinic to vaginal lubricant or tap water, and also found low rates of unsatisfactory Pap smears with no difference between the 2 groups. Although this study had only 70% power to find a difference of 5% in the rate of unsatisfactory smears, the results were consistent with those of Amies et al.

Another teaching that remains with me from medical school is that vaginal lubricant is bacteriostatic and thus interferes with the accuracy of cultures for gonorrhoea or chlamydia. This question is clinically important because sexually transmitted diseases and cervical cancer screening are often done in concert. Evidence on this point is limited, and in vitro studies suggest that further research is needed.¹ DNA probes are often done instead of cultures for screening. A single small study suggests that lubricant is unlikely to have a large effect on chlamydia polymerase chain reaction sensitivity. However, a reduction in sensitivity of 10–20% could not be ruled out.² Further research is needed to answer these questions definitively.

Enhancing the comfort of women having speculum examinations is important for both quality of care and public health. More than 50% of women diagnosed with cervical cancer have never been screened or have not had a Pap smear in the previous 3 years.³ Less discomfort associated with the exam may increase the likelihood that women return for screening at regular intervals. Kudos to Doctors Amies and Harer for addressing this small but important aspect of clinical practice. Their findings have changed my practice and should change the practice of others as well. Patient comfort during Pap smears will affect compliance and may ultimately improve our ability to prevent mortality from cervical cancer.