Cryopreserved embryos in the United States and their availability for research.

OBJECTIVE To determine the number of embryos stored at assisted reproductive technology (ART) clinics in the United States and their current disposition. DESIGN A targeted survey instrument sent by the SART-RAND team to all medical practices providing in vitro fertilization services in the United States. RESULTS The SART-RAND team surveyed all 430 ART practices in the United States. Of these practices, 340 returned surveys for analysis. The data from these surveys were merged with data taken from the 1999 SART dataset, which contains information about practice size and success rates. Responding clinics reported a total of 396,526 embryos in storage as of April 11, 2002. The vast majority of the embryos (88.2%) were targeted for patient use. Small numbers of embryos were available for research, donation, destruction, quality assurance, or other uses. CONCLUSIONS Nearly 400,000 embryos are stored in the United States, the majority of which (88.2%) are targeted for patient use. Few are available for research (2.8%), limiting possible conversion into embryonic stem cell lines.