Treatment of pregnant women with asymptomatic bacterial vaginosis with clindamycin
Systematic review
|Updated
Key message
Bacterial vaginosis is present in up to 20 % of women during pregnancy, and is associated with complications such as preterm birth. Approximately half of the infected pregnant women are asymptomatic. Asymptomatic pregnant women with bacterial vaginosis and without a medical history of preterm births are usually not treated with antibiotics in Norway.
We searched systematically for articles in international databases, included articles that met our inclusion criteria, critically appraised and summarised the results descriptively or in meta-analysis. We included seven randomized controlled clinical trials showing that:
- Clindamycin is associated with little or no change in the risk of preterm birth before 37 weeks when administered to pregnant women with asymptomatic bacterial vaginosis. This applies when the treatment is given during the second trimester and if treatment is given before 20 weeks gestation. Our quality assessments suggest that the quality of the evidence is moderate.
- Treatment of asymptomatic bacterial vaginosis with clindamycin is probably associated with little or no difference in the incidence of low birth weight or postpartum uterus infections. Our quality assessment suggest that the quality of the evidence is low for these outcomes, implying that further research is likely to change the effect estimates.
- The quality of available research is too low to determine whether treatment with clindamycin can reduce the risk of preterm birth before 33 week gestation. This conclusion applies both if the treatment is given during the second trimester and if treatment is given before 20 week gestation (early treatment).
Summary
Treatment of pregnant women with asymptomatic bacterial vaginosis with clindamycin - a systematic review
Background
Bacterial vaginosis is common among pregnant women in Norway and is associated with complications such as premature birth and low birth weight in the infant.
The effect of treating pregnant women with asymptomatic bacterial vaginosis without increased risk of premature birth is unclear, and is discussed both in Norway and in other countries. It is important to assess the effectiveness of treatment because screening and treatment of pregnant women without high risk of premature birth can increase resistance to antibiotics and result in higher treatment costs. Consequently, pregnant women with asymptomatic bacterial vaginosis are currently not treated with antibiotics in Norway.
Professor Harald Moi of Olafiaklinikken, Rikshospitalet asked the Norwegian Knowledge Centre for Health Services (Knowledge Centre) in 2009 to review national and international research on clindamycin treatment to pregnant women with asymptomatic bacterial vaginosis in second trimester.
Method
We searched for systematic reviews and randomized controlled trials in the following databases in July 2009:
• OVID MEDLINE
• OVID EMBASE
• Cochrane Database of Systematic Reviews (CDSR)
• Cochrane CENTRAL
• Database of Abstracts of Reviews of Effects (DARE Cochrane)
• HTA and NHS EED in the Cochrane library
• Clinical evidence
The search for systematic reviews was limited to the publication date from 2004. The search for randomized controlled trials was limited to the publication date from 2004 in the Cochrane CENTRAL and 2006 in MEDLINE and EMBASE.
Inclusion criteria:
Study design: Systematic reviews and randomized controlled trials
Population:
Pregnant women with asymptomatic bacterial vaginosis
Interventions:
Clindamycin in second trimester (13-27. weeks)
Control:
No treatment or placebo
Outcome:
Incidence of preterm birth (before 37 and before 33 weeks gestation), incidence of low birth weight (<2500 g), incidence of postpartum uterine infection Language:
Articles in English and Scandinavian.
We searched systematically for articles in relevant international databases, included articles that met our inclusion criteria, critically appraised and summarised the results descriptively or in meta-analysis. The quality of the evidence was assessed with Grading of Recommendations Assessment, Development and Evaluation (GRADE).
Results
The search yielded 131 unique references, of which 23 were reviewed in full text. Eleven articles were critically assessed. We used the identified systematic reviews to search for primary studies, leading to identification of seven randomised controlled trials. The results from these seven trials (including a total of 3225 women) were summarized in meta-analysis. Our summary showed that there was little or no difference whether pregnant women received clindamycin as compared to placebo/no treatment in terms of preterm birth before 37 weeks (OR 0.78 (0.57 to 1.07)). The summary also showed that there was little or no difference whether pregnant women received clindamycin before 20 weeks compared with placebo or no treatment, measured on preterm birth (OR 0.71 (0.44 to 1.14)). We assessed the quality of this documentation to be moderate. It is therefore likely that further research will affect our confidence in the effect estimate. Further research can also change the estimate.
Discussion
As shown in this review, there are many systematic reviews and controlled trials that evaluated the effect of clindamycin. The conclusions from these reviews show, that treatment with clindamycin might not prevent preterm birth before 37 weeks. Preterm birth before 37 weeks is not necessary associated with complications in the developed countries, as preterm birth before 33 weeks. We tried to summarise studies that reported preterm birth before 33 weeks, but few relevant studies with methodological flaws and serious heterogeneity prevented us to pool the results.
Conclusion
Clindamycin treatment of pregnant women with asymptomatic bacterial vaginosis leads to little or no change in the risk of preterm birth before 37 weeks. The quality of the evidence is considered to be of moderate quality, and apply both if therapy is given during the second trimester and if treatment is given before 20 week gestation (early treatment). Treatment with clindamycin in the second trimester does not seem to affect the risk of low birth weight or postpartum uterine infections, but for these outcome measures the quality of the evidence is considered to be low, suggesting that further research is likely to change the effect estimates. The quality of the evidence is too low to determine whether treatment with clindamycin affects the risk of preterm birth before 33 week gestation.
Needs for further research
There is a need for randomized controlled trials that evaluates the effect of early treatment of pregnant women with asymptomatic bacterial vaginosis (< 20. gestational week) on incidence of preterm births before 33 weeks and incidence of very low birth weight (<1500 g).
About Norwegian Knowledge Centre for the Health Services
Norwegian Knowledge Centre for the Health Services summarizes and disseminates evidence concerning the effect of treatments, methods, and interventions in health services, in addition to monitoring health service quality. Our goal is to support good decision making in order to provide patients in Norway with the best possible care. The Centre is organized under The Directorate of Health, but is scientifically and professionally independent. The Centre has no authority to develop health policy or responsibility to implement policies.