PREIMPLANTATION GENETIC DIAGNOSIS INCREASES THE IMPLANTATION RATE IN HUMAN IN-VITRO FERTILIZATION BY AVOIDING THE TRANSFER OF CHROMOSOMALLYABNORMAL EMBRYOS

Objective: To verify the percentage of chromosomally abnormal preimpla ntation embryos in patients with a poor prognosis and possibly to incr ease the chance of implantation by selecting chromosomally normal embr yos. Design: A prospective, randomized, controlled study. Setting: In vitro fertilization program at the Reproductive Medicine Unit of the S ociety Italiana Studi Medicina della Riproduzione, Bologna, Italy. Pat ient(s): In a total of 28 stimulated cycles, the maternal age was grea ter than or equal to 38 years and/or the patient had greater than or e qual to 3 previous IVF failures, factors that indicated a poor prognos is. After consent, 11 patients underwent preimplantation genetic diagn osis for aneuploidy, whereas 17 controls underwent assisted zona hatch ing. Intervention(s): Simultaneous analysis of chromosomes X, Y, 13, 1 8, and 21 in a blastomere biopsied from day-3 embryos. Chromosomal ana lysis was performed with fluorescence in situ hybridization. Assisted zona hatching was performed on day-3 embryos from the control-group pa tients. Main Outcome Measure(s): Embryo morphology, results of fluores cence in situ hybridization, clinical pregnancies, and implantation. R esult(s): In the study group, a total of 61 embryos were analyzed by f luorescence in situ hybridization, and 55% were chromosomally abnormal . Embryo transfer with at least one normal embryo was performed in 10 cycles. Four clinical pregnancies resulted, with a 28.0% implantation rate. In the control group, 41 embryos were transferred in 17 cycles a fter the assisted zona hatching procedure, yielding four clinical preg nancies and an 11.9% implantation rate. Conclusion(s): Infertile patie nts classified as having a poor prognosis have a high percentage of ch romosomally abnormal embryos. The advantage of selecting and transferr ing embryos with normal fluorescence in situ hybridization results has an immediate impact on implantation. (C) 1997 by American Society for Reproductive Medicine.