Relationship between peak serum estradiol levels and treatment outcome in in vitro fertilization cycles after embryo transfer on day 3 or day 5

Objective: To examine the relationships between peak serum estradiol (E,) levels and treatment outcome in in vitro fertilization (IVF) cycles after embryo transfer (ET) oil day 3 or day 5. Design: Retrospective analysis of 697 IVF-ET cycles between January 1999 and December 2001. Setting: A university-affiliated assisted reproduction program. Patient(s): Infertile patients undergoing IVF-ET cycles. Intervention (s): Peak E, concentration in serum was determined on the day of human chorionic gonadotropin (hCG) administration. The IVF-generated embryos were Cultured for 2 days until transfer on day 3. If more than four 8-cell embryos were present on day 3, embryo culture was continued until day 5 for blastocyst transfer. Main Outcome Measure(s): Clinical pregnancy rates. Result(s): High peak E, levels did not adversely affect treatment outcome. After the cycles were divided according to the day of ET, high peak E-2 levels were associated with improved pregnancy rates after ET on day 5 but not on day 3. Conclusion(s): Increasing peak E, levels in IVF cycles are associated with improved pregnancy rates after ET on day 5. (C) 2003 by American Society for Reproductive Medicine.