Objective: To evaluate the quantity and use of embryos cryopreserved at assisted reproductive technology (ART) clinics in the United States from 2004 through 2013 and to characterize trends in ART cycles in which all embryos were cryopreserved.
Design: Retrospective analysis.
Setting: Not applicable.
Patients: Registry data from the Society for Assisted Reproductive Technology.
Interventions: Historical cohort of U.S. ART cycles reported to the Society for Assisted Reproductive Technology Clinical Outcomes Reporting System between 2004 and 2013.
Main outcome measures: Number of embryos cryopreserved and factors associated with having cryopreserved embryos.
Results: The percentage of fresh cycles in which all embryos were frozen increased dramatically each year after 2010: 15.6% (2010), 19.9% (2011), 30.7% (2012), and 40.7% (2013). During 10 years, 1,954,548 embryos were cryopreserved and 717,345 embryos were transferred. In freeze-only cycles from 2004 to 2013, there was a significant increase in the percentage of women with diminished ovarian reserve (19.9% to 34.1%) and in those who used preimplantation genetic testing (3.2% to 6.9%). During the 10-year period, there were 294,575 fresh cycles with embryo transfer and at least one embryo cryopreserved. Overall, 52.5% (n = 154,543) did not undergo a subsequent frozen embryo transfer, 29.5% (n = 40,462) were left with no frozen embryos, 50.4% (n = 68,875) had one-five embryos, and 20.0% (n = 27,396) had ≥six. Factors associated with having excess embryos included donor oocyte cycles and increased antimüllerian hormone levels.
Conclusions: There has been a sharp increase in U.S. ART cycles in which all embryos are frozen and this may result in more embryos in storage.
Keywords: Embryo cryopreservation; embryo disposition; in vitro fertilization.
© 2020 The Authors.