EMBRYOS CULTURED IN-VITRO WITH MULTINUCLEATED BLASTOMERES HAVE POOR IMPLANTATION POTENTIAL IN HUMAN IN-VITRO FERTILIZATION AND INTRACYTOPLASMIC SPERM INJECTION

The aim of the present study was to investigate pregnancy rates ensuin g from transfer of embryos with multinucleated blastomeres. In our in- vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) prog ramme, 1735 embryo transfers were performed from January 1, 1995 to Au gust 31, 1996, In 136 of these transfers at least one embryo with one or more multinucleated blastomeres was present per transfer (study gro up). For each of these 136 transfers, two matched controls with transf er of exclusively mononucleated embryos were selected (control group). Matching was carried out according to age, method of fertilization (I VF or ICSI), number of transferred embryos and quality score of transf erred embryos. In the study group, there were eight transfers of exclu sively multinucleated embryos from which one pregnancy ensued and 128 transfers in which multinucleated and mononucleated embryos were trans ferred together leading to 23 pregnancies. The overall clinical pregna ncy rate per transfer was 16.9 % in the study group versus 25.7% in th e control group (P = 0.01), The ongoing pregnancy rate per transfer wa s 13.2% in the study group versus 23.2% in the control group (P = 0.03 ), The implantation rate per transferred embryo was 6.0% in the study group versus 11.3% in the control group (p = 0.003), This study shows that embryos with one or more multinucleated blastomeres have a poorer implantation potential than embryos,vith mononucleated blastomeres, T ransfer of embryos with multinucleated blastomeres should hence only b e considered when insufficient numbers of embryos with only mononuclea ted blastomeres are present.