Background: Early-onset group B streptococcus disease, recognized as the most common cause of early onset neonatal sepsis in developed countries, is transmitted vertically from the group B streptococcus carrier mother to the neonate in the peripartum. Accordingly, early-onset group B streptococcus disease is prevented by halting the transmission of the microorganism from the mother to the infant. Two main methods, routine culture-based screening and risk-based management, may be used in the identification of mothers requiring intrapartum antibiotic prophylaxis in labor. While there are advantages and disadvantages to each, there is limited high level evidence available as to which method is superior.
Objectives: To identify the effectiveness of risk-based management versus routine culture-based screening in the prevention of early-onset group B streptococcus disease in the neonate.
Inclusion criteria: Types of participants
This review considered studies which treated pregnant women with IAP following risk- and culture-based protocols for the prevention of early-onset group B streptococcus disease in the neonate.
Types of intervention
This review considered studies that evaluated risk-based management against routine culture-based screening for the prevention of early-onset group B streptococcus disease in the neonate.
Types of studies
This review looked for highest evidence available which in this case consisted of one quasi experimental study and eight comparative cohort studies with historical or concurrent control groups.
Types of outcomes
Incidence of early-onset group B streptococcus disease in neonates as measured by positive group B streptococcus culture from an otherwise sterile site. Secondary outcomes include neonatal death due to group B streptococcus sepsis and percentage of women who received intrapartum antibiotic prophylaxis.
Search strategy: A multi-step search strategy was used to find studies which were limited to the English language and published between January 2000 and June 2013.
Methodological quality: The quality of the eligible studies was assessed independently by two reviewers using the Joanna Briggs Institute quality assessment tool for observational studies.
Data collection: Data was extracted using a standardized extraction tool from the Joanna Briggs Institute.
Data synthesis: Quantitative papers were, where possible, pooled for meta-analysis using Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument effect sizes expressed as odds ratio and their 95% confidence intervals were calculated. Heterogeneity was assessed statistically using the standard Chi-square.
Results: The results of this review come from nine studies published in peer reviewed journals. The treatment group consists of those screened as per the culture-based protocol, the control group the risk-based protocol. For combined term and preterm infants the odds of early-onset group B streptococcus disease for the treatment vs control groups is 0.45 (95% CI 0.37 to 0.53). The odds ratio in term infants is 0.45 (95% CI 0.36 to 0.57). Preterm infants are four times (OR 4.20 [95% CI 3.36 to 5.24]) more likely to develop early-onset group B streptococcus disease than term infants regardless of prevention technique. One study provides information on neonatal mortality in which there is one neonatal death in the risk-based cohort and none in the culture-based. The rate of administration of IAP in this data set is greater in women exposed to the culture-based protocol than those exposed to the risk-based protocol, 29 and 19 per cent respectively (OR 1.69 95% CI = 1.60, 1.78).
Conclusions: This review analyses outcomes separately for term and preterm infants to account for prematurity as a confounding factor for early-onset group B streptococcus disease. The results favor the culture-based protocol over the risk-based protocol for the prevention of early-onset group B streptococcus disease in term infants. The difference in early-onset group B streptococcus disease incidence however for each method is small. Factors to consider when selecting one protocol over the other are: a) early-onset group B streptococcus disease incidence b) rates of intrapartum antibiotic prophylaxis and antibiotic exposure and c) the medicalization of birth. The review is limited by the low level of evidence available on this topic.
Implications for practice
There are advantages and disadvantages to both early-onset group B streptococcus disease prevention strategies. Women should be enabled to make informed decisions about their options for early-onset group B streptococcus disease prevention and be supported in this by clinicians. Adherence to either protocol by maternity care providers must be high for best outcomes.
Implications for research
Higher-level evidence such as randomized controlled trials are required to inform decision making in this area. Other research could involve vaccination for group B streptococcus and rapid group B streptococcus bedside testing, which would reveal maternal group B streptococcus culture status in the intrapartum. Surveillance of sepsis patterns and the long-term effects of antibiotics on the neonate in the intrapartum would help to guide clinical judgment.