Utilization and success rates of unstimulated in vitro fertilization in the United States: an analysis of the Society for Assisted Reproductive Technology database

Objective: To examine the utilization and outcomes of natural cycle (unstimulated) IVF as reported to the Society of Assisted Reproductive Technology (SART) in 2006 and 2007. Design: Retrospective analysis. Setting: Dataset analysis from the SART Clinical Outcome Reporting System national database. Patient(s): All patients undergoing IVF as reported to SART in 2006 and 2007. Intervention(s): None. Main Outcome Measure(s): Utilization of unstimulated IVF; description of patient demographics; and comparison of implantation and pregnancy rates between unstimulated and stimulated IVF cycles. Result(s): During 2006 and 2007 a total of 795 unstimulated IVF cycles were initiated. Success rates were age dependent, with patients <35 years of age demonstrating clinical pregnancy rates per cycle start, retrieval, and transfer of 19.2%, 26.8%, and 35.9%, respectively. Implantation rates were statistically higher for unstimulated compared with stimulated IVF in patients who were 35 to 42 years old. Conclusion(s): Unstimulated IVF represents <1% of the total IVF cycles initiated in the United States. The pregnancy and live birth rates per initiated cycle were 19.2% and 15.2%, respectively, in patients <35 years old. The implantation rates in unstimulated IVF cycles compared favorably to stimulated IVF. Natural cycle IVF may be considered in a wide range of patients as an alternative therapy for the infertile couple. (Fertil Steril (R) 2013; 100: 392-5. (C) 2013 by American Society for Reproductive Medicine.)