GnRH Antagonist to Prepare Recipients for Embryo Transfer

Inclusion Criteria: * History of infertility before cryopreserving the embryos or inability to conceive from her own oocytes (based on age and/or a serum FSH \> 15 IU/L). * Any patient desiring to become pregnant as a result of transferring frozen-thawed embryos generated using her own or donor oocytes. * Subject is in good health as determined by the Investigator on the basis of medical history, physical examination and laboratory screening tests. * A negative pregnancy test prior to starting treatment with estrogens. Exclusion Criteria: * Women with a history of liver and/or kidney disease * Hypertension: systolic pressure over 180 mm Hg or diastolic pressure over 105 at any study visit, measured twice 6 hours apart despite active treatment for hypertension. * Liver function tests of two times than the upper limit of normal * Women with active sever endometriosis.