Description:

Fertilized eggs (embryos) may be stored long-term in the frozen state. It allows couples undergoing IVF to have excess embryos stored for future pregnancy attempts without the expense and complexity of a fresh IVF cycle. The embryos are stored in special containers of liquid nitrogen in the IVF laboratory. The length of freezing apparently does not affect the likelihood of pregnancy.

Indications:

The most common indication for embryo freezing is to preserve and store excess embryos produced in IVF. In situations where fresh embryo transfer is not feasible (such as when the female partner becomes ill between egg retrieval and embryo transfer), a frozen embryo transfer is an alternative.

Contraindications, complications, adverse effects:

The freeze-thaw process may reduce the likelihood of embryo survival and the chance of pregnancy. It is not unusual to see only 50% of embryos surviving the thaw. Poor quality embryos are less likely to survive this process. There is no evidence for an increase in birth defects or chromosomal abnormalities as a result of the freeze-thaw process, however.