title: The power of meta-analysis to address an important clinical question in obstetrics.
abstract: After 17 years of collaborative research, a meta-analysis of randomized controlled trials on cerclage for singleton gestations with a prior spontaneous preterm birth and with a short transvaginal ultrasound cervical length <25mm before 24 weeks led to new clinical recommendations worldwide. This is an example of the power of meta-analyses, of why I like them, and why I think you should like them too. Many societies rank meta-analyses of randomized controlled trials as the best level of evidence, even above that of a single randomized controlled trial.
authors.affiliation: Jefferson Medical College, Philadelphia, PA. Electronic address: vincenzo.berghella@jefferson.edu.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Berghella
mesh_terms: D023802:Cerclage, Cervical; D005260:Female; D006801:Humans; D015201:Meta-Analysis as Topic; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic
keywords: Meta-analysis; cerclage; evidence-based medicine; randomized controlled trial