Introduction: Freezing-unfreezing procedures are essential when hyperestimulation is followed by embryo overproduction; they lower costs and increase pregnancy rates per aspiration. Objectives: To present our experience with embryo freezing-unfreezing. Setting: Assisted Reproduction Medical Service and Laboratory, Clinica Ricardo Palma. Design: Clinical retrospective study. Biologic material: Embryos obtained by assisted fertilization. Interventions: Controlled ovarian hyperestimulation with short luteal phase, ova capture at 36 hours post hCG administration, classical in vitro fertilization or ICSI-transport, classical processes of embryo cryopreservation and unfreezing. Main outcome measures: Embryo survival in freezing-unfreezing process. Results: We started our study in October 2003. Number of cycles with frozen embryos during this period was 154; from these we unfroze only 58. Pregn...

Introduction: Freezing-unfreezing procedures are essential when hyperestimulation is followed by embryo overproduction; they lower costs and increase pregnancy rates per aspiration. Objectives: To present our experience with embryo freezing-unfreezing. Setting: Assisted Reproduction Medical Service and Laboratory, Clinica Ricardo Palma. Design: Clinical retrospective study. Biologic material: Embryos obtained by assisted fertilization. Interventions: Controlled ovarian hyperestimulation with short luteal phase, ova capture at 36 hours post hCG administration, classical in vitro fertilization or ICSI-transport, classical processes of embryo cryopreservation and unfreezing. Main outcome measures: Embryo survival in freezing-unfreezing process. Results: We started our study in October 2003. Number of cycles with frozen embryos during this period was 154; from these we unfroze only 58. Pregn...