In vitro fertilization-induced alterations in coagulation and fibrinolysis as measured by thromboelastography.

Supraphysiologic increases in estrogen produced by in vitro fertilization (IVF) promote the expression of hemostatic markers. Although quantitative studies of individual markers have been performed during IVF, their results are conflicting and do not reveal the qualitative effect of each marker on the overall coagulation and fibrinolytic processes. Thrombelastograph® (TEG®) coagulation analysis, by contrast, provides a global measure of coagulation and fibrinolysis and can indicate the relative contributions of clotting factors, fibrinogen, and platelets to each process. We studied the serum estrogen concentrations and TEG® variables in 24 women at the beginning and conclusion of an IVF stimulation cycle. Serum estradiol (E 2 ) concentrations (mean ± so) increased from 26.9 ± 8.6 to 2098 ± 913 pg/mL (P < 0.005) at baseline and oocyte retrieval, respectively. The measured TEG® indices demonstrated alterations in coagulation rather than fibrinolysis. Although significant changes were noted in both the clot formation time and the coagulation index (P < 0.005), all TEG® values remained within the normal range. In addition, an increased role of fibrinogen in promoting clot strength was observed. These findings may assist in the treatment of IVF patients who ultimately develop thromboembolic complications as a result of ovarian hyperstimulation.