INCIDENCE OF CHROMOSOMAL-ABNORMALITIES FROM A MORPHOLOGICALLY NORMAL COHORT OF EMBRYOS IN POOR-PROGNOSIS PATIENTS

Purpose: Preimplantation genetic diagnosis of aneuploidy was performed on the embryos yielded by 70 poor-prognosis patients, with the aim of transferring those with a normal chromosomal complement, thus possibl y increasing the chances of pregnancy. Methods: Multicolor fluorescenc e in situ hybridization (FISH) uas applied for the simultaneous detect ion of chromosomes X, Y, 13, 16, 18, and 21. Inclusion criteria were ( 1) a maternal age of 36 years or older (n = 33), (2) three or more pre vious in vitro fertilization cycles (n = 20), and (3) art altered kary otype (n = 17). Results: A total of 412 embryos underwent FISH, result ing in 234 (57%) that were chromosomally abnormal. Euploid embryos wer e available for transfer in 59 patients, generating 19 pregnancies (32 %), with an implantation rate of 19.9%. Conclusions: High rates of chr omosomally abnormal embryos in poor-prognosis patients can determine r epeated in vitro fertilization failures when embryo selection is perfo rmed on the basis of morphological criteria alone. Hence, the FISH ana lysis could represent the prevailing approach for the identification o f embryos possessing full potential for developing to term.