Can pregnant women obtain their own specimens for group B streptococcus? A comparison of maternal versus physician screening

Objective — We aimed to compare the Group B Streptococcus (GBS) detection rate when pregnant women performed their own vaginal/anorectal swabs with that from the standard practice of physician-performed swabs.

Method — The research involved a comparison of maternally obtained swabs for GBS with the current gold standard of physician-obtained swabs performed on the same patient. The women were surveyed about who they would prefer to do their swabs. This research was carried out in the offices of five family physicians and eight obstetricians at Mount Sinai Hospital, Toronto–a tertiary-care teaching hospital–between 1 November 1995 and 31 March 1996. The patients were consecutive pregnant women presenting for their 26-28 weeks antenatal visit. Patients were given a questionnaire and instructions describing how to perform a vaginal/anorectal swab. After each patient completed the survey and obtained her own GBS culture, the physician collected a GBS specimen in their usual manner. The main outcome measures were the results of self-performed and physician-obtained combined vaginal/anorectal culture specimens.

Results — Sixty-three matched pairs of GBS swab results and 161 patient surveys were collected. Using any positive result as the gold standard, the prevalence of GBS was 39 out of 163 (24%). Patients detected 38 cases for a sensitivity of 97% (lower 95% confidence limit 92), while physicians identified 32 cases for a sensitivity of 82% (95% confidence limit 70-94). Twenty-five per cent of the women preferred that the physician take the swab, while 75% were indifferent or preferred to self-swab.

Conclusions — Patient-collected vaginal/anorectal swabs for GBS are at least as sensitive as the current practice of physician-performed swabs. The majority of participating patients were interested or willing to perform their own swab. Self-swabbing involves women more actively in their obstetrical care and may improve physician compliance with screening guidelines.