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 obtained after ICSI, 40% of the embryos do not survive the cryopreservation procedure. After selective transfer of further cleaving frozen-thawed embryos, pregnancy loss was 31% (subclinical pregnancy rate of 13% and miscarriage 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 further follow-up of the children born indicate that cryopreservation of ICSI embryos is a safe procedure, long term follow-up of the children born however is still warranted.