Preimplantation genetic diagnosis increases the implantation rate in human in vitro fertilization by avoiding the transfer of chromosomally abnormal embryos.

OBJECTIVE

To verify the percentage of chromosomally abnormal preimplantation embryos in patients with a poor prognosis and possibly to increase the chance of implantation by selecting chromosomally normal embryos.

DESIGN

A prospective, randomized, controlled study.

SETTING

In vitro fertilization program at the Reproductive Medicine Unit of the Società Italiana Studi Medicina della Riproduzione, Bologna, Italy.

PATIENT(S): In a total of 28 stimulated cycles, the maternal age was > or = 38 years and/or the patient had > or = 3 previous IVF failures, factors that indicated a poor prognosis. After consent, 11 patients underwent preimplantation genetic diagnosis for aneuploidy, whereas 17 controls underwent assisted zona hatching.

INTERVENTION(S): Simultaneous analysis of chromosomes X, Y, 13, 18, and 21 in a blastomere biopsied from day-3 embryos. Chromosomal analysis was performed with fluorescence in situ hybridization. Assisted zona hatching was performed on day-3 embryos from the control-group patients.

MAIN OUTCOME MEASURE(S): Embryo morphology, results of fluorescence in situ hybridization, clinical pregnancies, and implantation.

RESULT(S): In the study group, a total of 61 embryos were analyzed by fluorescence 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 after the assisted zona hatching procedure, yielding four clinical pregnancies and an 11.9% implantation rate.

CONCLUSION(S): Infertile patients classified as having a poor prognosis have a high percentage of chromosomally abnormal embryos. The advantage of selecting and transferring embryos with normal fluorescence in situ hybridization results has an immediate impact on implantation.