Indications

Embryo freezing or cryopreservation is useful to preserve leftover embryos after a cycle of in vitro fertilization, as patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle again. Or, if pregnancy occurs, they could return later for another pregnancy. 

Method

The main techniques used for embryo freezing are vitrification versus slow programmable freezing (SPF). Studies indicate that vitrification is superior or equal to SPF in terms of survival and implantation rates.