The power of meta-analysis to address an important clinical question in obstetrics

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.