Journal of the European Society for Gynaecological Endoscopy


Letter to the editor

G. Page

Jan Ypermansziekenhuis, Dept. Obstetrics & Gynaecology, Briekestraat 12, 8900 Ieper, Belgium

Correspondence at:

Published online: Jan 14 2014

Dear editor,

EBM tools to gather the best evidence for interventions in in vitro fertilisation programmes. Evidence-based reproductive medicine as stated by M. Dhont (M. Dhont, 2013) a co-ordination between clinicians and reviewers (methodologists) is necessary to ­conduct adequate clinical trials and meta-analyses. However, although live birth rate might be the gold standard, ongoing pregnancy as outcome is quite comparative and sufficient to serve as a reliable outcome in interventions (Clarke and Van Rumste, 2010). Moreover, EBM offers other tools than large scale multi-centric clinical trials to get solid ­evidence for reproductive interventions. First of all, registering all trials before starting could avoid ­multiple efforts on the same topic. Secondly, sample size calculations of new trials are to be determined by the current evidence in published meta -analyses (building cumulative meta-analyses) (Lau et al., 1995) and will result in less scaled trials to reach sufficient evidence to guide clinical practice. Thirdly, Time Sequential Analysis (Wetterslev et al., 2008) helps to determine if a meta-analysis contains enough evidence to perform or withhold a certain intervention, avoiding the further conduction of ­unnecessary trials.


Dhont M. Evidence-based reproductive medicine: a critical ­appraisal. FV&V in ObGyn, 2013;5:233-40.
Clarke J, van Rumste M, Farquhar CM et al. Measuring outcomes in fertility trials: can we rely on clinical pregnancy rates? Fertil Steril. 2010;94:1647-51.
Lau J, Schmid C, Chalmers TC. Cumulative meta-analysis of clinical trials builds evidence for exemplary medical care. J Clin Epidemiol. 1995;48:45-57.
Wetterslev J, Thorlund K, Brok J et al. Trial sequential analysis may establish when firm evidence is reached in cumulative meta-analysis. J Clin Epidemiol. 1008;61:64-75.


Dear Dr Page,

Thank you for the interest in my paper on Evidence Based Medicine in Reproductive Medicine and your thoughtful comments. The paper was not meant as an in depth discussion of all aspects of EBM and how to gather the best evidence but was focused on some procedures used in in vitro fertilization. I completely agree with your suggestions for optimizing clinical trials such as registering all trials before starting and a judicious sample size calculation. They are a welcome and much appreciated complement to my paper.

Marc Dhont
Department of Obstetrics and Gynaecology
Ghent University Hospital
De Pintelaan 185
9000 Gent, Belgium