Study of Group B Streptococcus in Pregnancy
Author Information
Author(s): Jean R. Goodman, Richard L. Berg, Robert K. Gribble, Paul R. Meier, Susan C. Fee, Paul D. Mitchell
Primary Institution: Marshfield Clinic
Hypothesis
What is the prevalence of group B streptococcus (GBS) in pregnant women and how predictive are GBS cultures obtained in each trimester of pregnancy for GBS status at delivery?
Conclusion
Antenatal GBS cultures are poor predictors of maternal GBS carriage at delivery, regardless of when they are done.
Supporting Evidence
- GBS carriage was 14.0% in the first trimester and 12.1% at delivery.
- Only 3.8% of patients were continuously positive for GBS across all cultures.
- The negative predictive value of a culture at 37 weeks was 95%.
Takeaway
This study looked at how common a germ called group B streptococcus is in pregnant women and found that tests done during pregnancy don't really help predict if a mother will have it when she gives birth.
Methodology
Lower vaginal/perianal GBS cultures were obtained in the first trimester, at 26-28 weeks, at 37 weeks, and on admission for delivery, with sensitivity, specificity, and predictive values calculated.
Limitations
The study had a lower than expected prevalence of GBS, which may limit the generalizability of the findings.
Participant Demographics
Most participants were white, 86% were married, and the mean age was 27.7 years.
Statistical Information
Confidence Interval
(95% confidence limits)
Statistical Significance
p<0.05
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