Reply: ‘Is it time for meta-analysis?’

Abstract

Is it time for a meta-analysis?Sir, Recent issue of the Hum Reprod Update included a meta-analysis by that systematically evaluated the current state of evidence regarding the effects of aspirin in IVF. The authors found non-significant point estimates for pregnancy, miscarriage and cancellation rates with confidence intervals overlapping the null hypothesis. Based on these results, the authors concluded that aspirin has no effect on pregnancy in IVF and as a result, suggest abandoning the treatment in clinical practice. We question the approach employed by these authors and, more importantly, suggest they have reached a flawed interpretation of their results.The random-effects modelling used by Gelbaya et al. has received much criticism in the published literature (Peto, 1987;Petitti, 1994). Random-effects models have an inherent loss of precision by introducing an in-between study variance, and make the dubious assumption that the set of trials included in the