Forest plot of two-stage Intention to Treat analysis, outcome: live birth. Analysis of studies that did share IPD combined with a recent, yet unpublished, study that did not (yet) share IPD. OR, odds ratio. 14 studies (5155 participants). Shown event numbers are observed values only. This forest plot shows the two-stage analysis of the 13 studies that were included in the IPD analysis combined with a single recent RCT that has been published while drafting this manuscript but that could not yet share IPD (Metwally et al., 2020). For the 13 studies that shared IPD, the per-study and pooled odds ratios are based on imputed data in our IPD dataset. The outcome ‘live birth’ was imputed for 100 participants (fraction of missing outcome data 2.4%). For the single study that did not share IPD (Metwally et al., 2020), the data were withdrawn from their manuscript. Numbers of missing data are unknown.