Objective: To evaluate the efficacy of zygote intrafallopian transfer (ZIFT) on implantation rates and pregnancy rates (PRs) in patients with repeated failure of implantation in IVF-ET cycles. Design: A case-control study. Patient(s): Criteria for patient selection included male factor or unexplained infertility, normal uterine cavity, and at least three failures of implantation in IVF-ET cycles in which at least three embryos were placed per transfer. Data on 70 patients who underwent 92 ZIFT cycles are presented. A control group consisted of patients with the same selection criteria who underwent an additional standard IVF-ET cycle during the same time period. Intervention(s): Ovulation induction consisted of down-regulation with GnRH analogue followed by ovarian stimulation with FSH and hMG. Intracytoplasmic sperm injection was performed on the oocytes of all patients with male factor infertility. Zygotes were transferred by laparoscopy into the fallopian tube 24-26 hours after oocyte retrieval. Main Outcome Measure(s): Implantation rates and PRs in the ZIFT and control groups were compared. Result(s): The PRs and implantation rates were significantly higher in the ZIFT group than in the control group: 34.2% (24/70) and 8.7% (29/333) versus 17.1% (12/70) and 4.4% (13/289), respectively (P = 0.002 and P = 0.04). The cumulative conception rate for two ZIFT cycles was 59.3%. Conclusion(s): Zygote intrafallopian transfer should be considered a beneficial mode of treatment for patients with repeated failure of implantation in IVF and transcervical ET. More prospective randomized studies are needed to support this observation.
- Implantation failure