[Value and limits of conventional or cumulative meta analysis in obstetrics and gynecology]

The authors describe some situations where meta-analyses would have been of great benefit if they have been done or sufficiently published. They emphasize several problems ensued by this new method: if possible, meta-analyses have to be done each time a new trial is analysed, according to a precise method. Cumulative meta-analysis should rely on a regular and prospective registration of clinical trials. In all cases, meta-analyses should be available to a large number of physicians, in the main interest of patients.