Introduction: A large-scale in situ simulation initiative on cardiac arrest in pregnancy was implemented across NYC Health + Hospitals. In situ simulation must be safely balanced with clinical conditions such as through application of no-go considerations or standardized reasons to cancel or postpone the simulation. Our objective is to describe our findings on the application of no-go considerations during this simulation initiative. Methods: NYC Health + Hospitals/Simulation Center developed an in situ simulation program focused on cardiac arrest in pregnancy, implemented at 11 acute care facilities. The program's toolkit included no-go considerations for in situ simulation safety: situations prompting a need to cancel, reschedule, or postpone a simulation to ensure patient and/or staff safety. Results: Data were collected from June 2018 through December 2019. The simulation sites reviewed the 13 established no-go considerations before each simulation event to assess if the simulation was safe to "go". After the conclusion of the initiative, all data related to no-go considerations were analyzed. Two hundred seventy-four in situ simulations were scheduled and 223 simulations (81%) were completed. Fifty-one no-go events were reported, with 78% identifying a reason by category. Twenty-two percent did not report a reason or category. Four of the 13 suggested no-go considerations were not reported. Conclusions: The no-go considerations framework promotes standardized and strategic scheduling of in situ simulation. Analysis of no-go consideration application during this system-wide initiative provides a model for the usage of tracking no-go data to enhance safety and inform future simulation planning.