Embryo freezing after intracytoplasmic sperm injection

This study reports on the safety and efficiency of the cryopreservation of human embryos obtained after intracytoplasmic sperm injection. For this, we evaluated the morphological survival, the capacity of the surviving embryo to develop further in vitro and in vivo. After freezing-thawing embryos ob tained after ICSI, 40% of the embryos do not survive the cryopreservation p rocedure. After selective transfer of further cleaving frozen-thawed embryo s, pregnancy loss was 31% (subclinical pregnancy rate of 13% and miscarriag e rate of 18%). As a result the livebirth rate per transferred embryos and per thawed embryo was 7 and 3% respectively. Obstetric outcome as well as f urther follow-up of the children born indicate that cryopreservation of ICS I embryos is a safe procedure, long term follow-up of the children born how ever is still warranted. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.