A controlled trial of natural cycle versus microdose gonadotropin-releasing hormone analog flare cycles in poor responders undergoing in vitro fertilization

Objective To determine the efficacy of natural-cycle IVF compared with controlled ovarian hyperstimulation in poor responders. Design Randomized, controlled study. Setting Private center for assisted reproduction. Patient(s) One hundred twenty-nine women who were poor responders in a previous IVF cycle. Intervention(s) Fifty-nine women underwent 114 attempts of natural-cycle IVF, and 70 women underwent 101 attempts of IVF with controlled ovarian hyperstimulation with microdose GnRH analog flare. Main outcome measure(s) Number of oocytes retrieved, pregnancy rate (PR) per cycle, PR per transfer, and implantation rate. Result(s) The poor responders treated with natural-cycle IVF and those treated with micro-GnRH analog flare showed similar PRs per cycle and per transfer. The women treated with natural-cycle IVF showed a statistically significant higher implantation rate (14.9%) compared with controls (5.5%). When subdivided into three groups according to age (≤35 years, ≥36-39 years, ≥40 years), younger patients had a better PR than the other two groups. Conclusion(s) In poor responders, natural-cycle IVF is at least as effective as controlled ovarian hyperstimulation, especially in younger patients, with a better implantation rate. © 2004 by American Society for Reproductive Medicine.