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.