BackgroundTranexamic acid is one component of a complex management algorithm for postpartum hemorrhage. In Japan, the 2010 obstetric hemorrhage management guidelines was revised in 2017, adding the recommendation for the administration of tranexamic acid for postpartum hemorrhage. This research aims to delineate the temporal trends in tranexamic acid administration in patients undergoing cesarean deliveries and to examine the impact of the obstetric hemorrhage management guidelines implementation. MethodsAn interrupted time series analysis was conducted on data from patients who underwent cesarean deliveries from April 2012 to August 2021, sourced from Japan’s nationwide health insurance claims database. We examined the trends of tranexamic acid usage and blood transfusion use before and after the implementation of the revised guidelines in 2017. ResultsThe study cohort comprised 91 166 cesarean deliveries. Prior to the guideline implementation, the rate of tranexamic acid usage decreased. Post-guidelines implementation, there was a statistically significant increase in the rate of tranexamic acid use, with a quarterly percentage change of 0.48% (95% confidence interval: 0.36 to 0.60; P < 0.001). The guidelines implementation in 2017 was not significantly associated with a change in the rate of transfusions. ConclusionsThis interrupted time series analysis demonstrated a significant increase in the rate of tranexamic acid administration following the implementation of the revised guidelines, reversing the previously observed downward trend. Our findings could reflect the impact of the revised guideline on the use of tranexamic acid for postpartum hemorrhage, but this did not translate to fewer blood transfusions.