Randomization and Masking
preeclampsia
EVENT, PREECLAMPSIA
Randomization was undertaken by the trial statistician through a computer-generated blocking list at the start of the trial. Random ordering was selected to minimize the rank correlation between the historical event rate and the order of implementation. The timing of implementation of the intervention to each center was revealed only 30 days before the implementation phase to prevent changes in practice before the implementation. However, due to delays with the implementation of the test analyzers and the availability of assays, the initiation of the intervention at sites 2 and 3 was delayed. Before completion of enrollment, the Trial Steering Committee approved the analysis of results according to when the intervention actually happened, rather than when it was originally planned.At the start of the trial period, all centers were in the preintervention phase. All patients presenting with suspected or diagnosed preeclampsia in this phase were managed according to local guidance. There was no standardization of protocols for preeclampsia treatment or delivery indication. Subsequently, every 4 months, 1 randomly allocated center transitioned to the implementation of the intervention. All centers continued the baseline data collection until randomized to implementation. Once each center crossed over to the intervention phase, the intervention was continued as part of routine care until the end of the study. After the last center has crossed over, the trial continued for a final period of 5 months during which all centers received the intervention. The effectiveness of the intervention was measured by comparing the aggregated data of the centers in the prerandomization phase (preintervention) of the trial with those in the postrandomization phase (post-intervention). Routine clinical data were collected for the trial on all participating patients.