Natural cycle in vitro fertilization implantation rates compared to stimulated in vitro fertilization and role of serum antimullerian hormone levels

Objective: The objective of this study is to compare implantation and singleton live birth rates between natural cycle in vitro fertilization (NCIVF) and stimulated IVF. Stratify the results by age and antimullerian hormone (AMH). Design: Retrospective cohort trial of patients who underwent unstimulated IVF between 2007 and 2011. Stimulated patient data from the 2010 Centers for Disease Control (CDC) report. Setting: Private practice. Patients: Infertility patients < 43-year-old. Intervention: None. Main Outcome Measures: (1) Implantation rates stratified by age and AMH (2) singleton pregnancy rates. Results: A total of 1288 cycles of NCIVF were compared to 94,976 cycles from CDC. In patients <35 years the implantation rates for NCIVF and stimulated IVF were 35.1% versus 36.9%. In patients 35-37, 38-40 and 41-42 years old, the NCIVF and stimulated IVF implantation rates were 33.9% versus 27.0%, 30.4% versus 17.7%, and 21.4% versus 9.6%. NCIVF implantation rates were independent of AMH at all ages and all levels of AMH. The singleton live birth rates per embryo transfer for both NCIVF and the CDC reported stimulated IVF were similar for all age groups. Conclusions: Implantation rates were superior in patients 35-40 undergoing NCIVF compared with stimulated IVF. In NCIVF implantation rate was independent of AMH. The live singleton birth rates per embryo transfer for NCIVF and stimulated IVF are similar.