To determine whether a transient hypercoagulable state is induced by the uterine artery embolization (UAE) procedure. Serial periprocedure blood samples were obtained from 27 patients undergoing the UAE procedure. Five blood samples were obtained from each patient at set time intervals: before the procedure (for baseline determination), immediately before and after embolization of the uterine arteries, 90 minutes after conclusion of the procedure, and between 18 and 24 hours later. Each blood sample was analyzed for the peripheral levels of the following parameters: thrombin-antithrombin complex (TAT), prothrombin fragment 1.2 (F1.2), platelet factor 4 (PF4), D-dimer, and plasmin-alpha(2)-antiplasmin complex (PAP). For each parameter, the baseline values were statistically compared with the pre- and postembolization values for each individual to detect change over time. Overall and global occasion effects for continuous variables were assessed with the Friedman statistic and individual comparisons between occasions with the Wilcoxon signed-rank test. No evidence was found for a difference in coagulability among the five occasions for D-dimer (P =.7645) or PF4 (P =.09). All three of the remaining measures were found to have statistically significant differences (P <.0001 for F1.2, P =.0026 for PAP, and P =.0006 for TAT). No evidence was found for a difference between preprocedure and preembolization levels for these three latter parameters (P =.595 for F1.2, P =.128 for PAP, P =.9705 for TAT). Hypercoagulability potential as measured by prothrombinase and F1.2 generation increased between preembolization samples and each of the successive postprocedure samples (P <.0001, P <.0001, P =.0082), whereas PAP increased at 90 minutes (P =.0023) and TAT increased immediately after embolization (P <.0001). No clinically apparent thrombotic complications occurred among any of the patients studied. Surrogate markers of hypercoagulability increase as a result of UAE, suggesting that a prothrombotic state may result after the procedure.