Since its introduction in 1978, over 3.75 million babies have been born using in vitro fertilization (IVF). Maturing ovarian follicles lead to a large rise in estrogen to supra-physiological levels . This increase in estrogen has been shown to cause a hypercoagulable state, leading at times to arterial and venous thrombosis.(Thromboelastogram (TEG) is a point of care whole blood hemostatsis analyzer mimicking in vivo conditions and measuring visco elastic properties of the clot. The TEG shows effect of most of the components of hemostatsis: coagulation factors, fibrinogen, platelets and fibrinolysis. Components of TEG include R, reflecting coagulation factor cascade, alpha angle and K measurements reflecting fibrin function, MA reflecting mostly thrombocyte function, coagulation index (CI) measuring global hemostatic statis and LY30 measuring fibrinolysis.

In this study the investigators would like to measure serum estrogen levels and (TEG) in parturients at the beginning and conclusion of an IVF simulation cycle and evaluate how it's influnence on coagulation parameters, and wheather or not a large sample size will effect primary outcomes.

Secondarily the investigators would like to see if estrogen levels are predictors of coagulation parameters and see if age influences TEG parameters

Inclusion Criteria:

• Parturients above 18 undergoing in-vitro fertilization at rabin medical center, with the ability to comply with the study requriments.

Exclusion Criteria:

Parturients were excluded if they had;

• hypertension,
• diabetes,
• anticoagulation therapy or any platelet disorder,
• or were not able to comply with study requirments.

Parturients undergoing in-vitro fertilization treatment