Vaginal-perianal cultures for GBS in pregnancy preferred

Vaginal-perianal cultures for group B streptococcal infections (GBS) during pregnancy yield results comparable to vaginal-rectal cultures and cause less patient discomfort, a new study reports.

Researchers used swabs to collect vaginal-perianal samples followed by vaginal-rectal samples from 193 women 18 years and older at 35 to 37 weeks’ gestation. The overall agreement rate between the 2 culture methods was 96.4% (186 women) for a sensitivity of 91.1% and specificity of 98.5%. GBS detection rates were similar. Patients reported an average pain level of 1.2 points on a 0 to 10 scale for vaginal-perianal culture compared with 3.4 points for vaginal-rectal culture. The study was published in Obstetrics and Gynecology (2011;118[2, Part 1]:313-317).

The study “adds to the current body of evidence that suggests that vaginal-perianal cultures may be a reasonable, patient-preferred alternative for the collection of recommended cultures for detection of GBS during pregnancy,” the researchers write.

More than two-thirds of the patients said that the vaginal-perianal method caused less discomfort than vaginal-rectal culture. Slightly more than half of patients reported no pain with vaginal-perianal culture compared with 18.7% for vaginal-rectal culture.

Noting that their study didn’t assess neonatal health status, the researchers suggest that future research “could monitor early onset GBS disease in neonates after switching to vaginal-perianal collection methods.”

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