Interpretation
Recently, a network meta-analysis developed by D’Antonio et al. to determine the role of progesterone, cerclage and vaginal pessary for decreasing the risk of PTB in an unselected population of twin pregnancies did not find an association between these treatments and a reduction in PTB or adverse maternal and perinatal outcomes6. However, differently from D’Antonio et al, in our NMA we identified a non-statistical reduction in PTB<34 when comparing pessary vs control (0.76; CI 0.55-1.06). In our study, a similar trend was also identified when considering only sPTB<34 (0.78; CI 0.49-1.25). It is important to clarify that our NMA included six studies comparing pessary vs control, a considerably large sample size when compared to previous studies and D’Antonio. This result raises the possibility that, with a powerful sample size, a significant decrease in PTB would be possible using a cervical pessary in twins.