Change in research site

Patients with a history of recurrent implantation failure who are planning a frozen embryo transfer (FET) are enrolled into the program. Patients are randomized to an endometrial biopsy prior to starting estrogen to prepare for the transfer of warmed vitrified embryos or to routine care.

Patients who failed to achieve a clinical pregnancy after embryo transfer of at least three high quality embryos in at least two IVF or FET cycles and for whom their last failed cycle was a frozen embryo transfer are offered the opportunity to enroll in this study. All patients will follow our routine FET protocol.

On a randomized basis, selected patients will undergo an endometrial biopsy using a Pipelle disposable device in the week prior to starting estrogen to prepare her endometrium.

Inclusion Criteria:

• At least two prior consecutive failed IVF or FET cycles with transfer of at least 3 high quality embryos and with last cycle a FET cycle

Exclusion Criteria:

• Alternate explanation for implantation failure (e.g., intrauterine pathology)