Natural-cycle in vitro fertilization in poor responder patients: a survey of 500 consecutive cycles.

Objective: To determine the role of the natural cycle for in vitro fertilization (IVF) in poor responder patients.

Design: Retrospective survey.

Setting: Private center for assisted reproduction.

Patient(s): 294 women who were poor responders in a previous IVF cycle.

Intervention(s): Analysis of 500 consecutive natural cycles IVF.

Main Outcome Measure(s): Number of cycles with oocytes, pregnancy rate per cycle, per transfer, and implantation rate.

Result(s): Oocytes were found in 391 cases (78.1%), and cleaving embryos suitable for transfer were obtained in 285 cycles (57.0%). Pregnancy was observed in 49 cases, with a pregnancy rate of 9.8% per cycle, 17.1% per transfer, and 16.7% per patient. The patients were subdivided arbitrarily by the women's age into three groups. Patients 35 years old or younger showed a pregnancy rate of 18.1% per cycle, 29.2% per transfer, and 31.7% per patient. Women aged between 36 and 39 years showed a pregnancy rate of 11.7% per cycle, 20.6% per transfer, and 20.3% per patient. Women 40 years old or older showed a pregnancy rate of 5.8% per cycle, 10.5% per transfer, and 9.7% per patient. No differences were found for any of the evaluated parameters, independent of which cycle was the first, the second, third, fourth, or fifth, or further consecutive cycle.

Conclusion(s): In poor responder patients, natural-cycle IVF is an effective treatment, especially in younger women.