Factors associated with the use of elective single-embryo transfer and pregnancy outcomes in the United States, 2004-2012.

Objective: To evaluate factors associated with elective single-embryo transfer (eSET) utilization and its effect on assisted reproductive technology outcomes in the United States.
Design: Historical cohort.
Setting: Not applicable.
Patient(s): Fresh IVF cycles of women aged 18-37 years using autologous oocytes with either one (SET) or two (double-embryo transfer [DET]) embryos transferred and reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System between 2004 and 2012. Cycles were categorized into four groups with ([+]) or without ([-]) supernumerary embryos cryopreserved. The SET group with embryos cryopreserved was designated as eSET.
Intervention(s): None.
Main Outcomes Measure(s): The likelihood of eSET utilization, live birth, and singleton non-low birth weight term live birth, modeled using logistic regression. Presented as adjusted odds ratios (aORs) and 95% confidence intervals (CIs).
Result(s): The study included 263,375 cycles (21,917 SET[-]cryopreservation, 20,996 SET[+]cryopreservation, 103,371 DET[-]cryopreservation, and 117,091 DET[+]cryopreservation). The utilization of eSET (SET[+]cryopreservation) increased from 1.8% in 2004 to 14.9% in 2012 (aOR 7.66, 95% CI 6.87-8.53) and was more likely with assisted reproductive technology insurance coverage (aOR 1.60, 95% CI 1.54-1.66), Asian race (aOR 1.26, 95% CI 1.20-1.33), uterine factor diagnosis (aOR 1.48, 95% CI 1.37-1.59), retrieval of ≥16 oocytes (aOR 2.85, 95% CI 2.55-3.19), and the transfer of day 5-6 embryos (aOR 4.23, 95% CI 4.06-4.40); eSET was less likely in women aged 35-37 years (aOR 0.76, 95% CI 0.73-0.80). Compared with DET cycles, the likelihood of the ideal outcome, term non-low birth weight singleton live birth, was increased 45%-52% with eSET.
Conclusion(s): Expanding insurance coverage for IVF would facilitate the broader use of eSET and may reduce the morbidity and healthcare costs associated with multiple pregnancies.
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