Many couples trying to get pregnant through in vitro fertilization (IVF) have their embryos frozen (cryopreserved) during the process. The indications for embryo freezing are multiple, from embryo banking for future use, to improving IVF success rates, to improved obstetrical outcomes. Doctor Mor’s IVF center has successfully performed this procedure with excellent results for many couples in the Los Angeles area.
Embryo freezing allows for storage of unused embryos for an indefinite amount of time. In vitro fertilization and egg donation cycles often result in more embryos than actually needed for transfer. After transfer of fresh embryos into the uterus, any remaining embryos which are suitable for freezing are cryopreserved. Embryos may be frozen at the day-1, day-3 stage or the day-5 or day-6 blastocyst stage. A frozen embryo transfer may then be performed at any future time in a simple short procedure.
There are various indications for embryo freezing beyond the storage of surplus embryos. In poor responders (patients who respond to injectable hormones with only a small number of eggs/embryos) for example, it may be necessary to perform several cycles of IVF/embryo freezing in order to accumulate enough embryos for a single embryo transfer. Similarly, in patients who require a combination ZIFT/IVF(see above), embryo banking may be necessary in order to obtain enough embryos for transfer both into the fallopian tubes as well as the uterus. Occasionally, a uterine abnormality may preclude transfer of fresh embryos, requiring storage of embryos until the uterus is normalized.
The California Center for Reproductive Health has extensive experience in embryo freezing. Although implantation rates for frozen-thawed embryos are generally lower than those for fresh embryos, success rates at our Center are still high, reaching live birth rates of 30-40%.