Results from meta-analyses significantly influence clinical practice. Both simulation and empirical studies have demonstrated that the risk of random error (i.e. spurious chance findings) in meta-analyses is much higher than previously anticipated. Hence, authors and users of systematic reviews and meta-analyses have a responsibility to carefully consider the risk of random errors to avoid misleading conclusions. Trial sequential analysis is a useful meta-analytic method for gauging the risk of random error in meta-analysis and the amount of additional evidence required to reach firm conclusions about the investigated intervention effect(s). We outline the rationale for conducting trial sequential analysis including some examples of the meta-analysis on antenatal magnesium for women at risk of preterm birth.