Embryo freezing (embryo cryopreservation)

What embryo freezing involves

The UK fertility regulator, the HFEA, says “Often with in vitro fertilisation (IVF) or Intracytoplasmic sperm injection (ICSI) treatment, there may be some good quality embryos left after embryo transfer. Instead of disposing them, there is the option to freeze them to use in the future (in case treatment doesn't work for example, or to try for a sibling).”

Not every embryo qualifies: “Not all embryos are suitable for freezing so only good quality embryos will be chosen to freeze.” And the stage varies: “Embryos can be frozen at different stages of their development – when they're just a single cell, at the two to eight cell stage or later in their development (called the blastocyst stage).” See blastocyst culture.

When it is used

The HFEA lists reasons including “You want the option of using your embryos in the future (rather than having a further fresh IVF or ICSI cycle).” and “Your treatment needs to be cancelled after egg collection (for example, if you over respond to fertility drugs). You should be offered the opportunity to have any suitable embryos frozen to use later.” It adds that “Embryos can also be frozen to preserve fertility so it may be possible to have a baby at a later date.” See fertility preservation. Whether it is appropriate in a particular case is a clinical decision for the treating doctor. This directory does not make that judgement.

What the regulator says about risks

The HFEA states: “Although most embryos do survive the freeze thaw process, some may not survive.” And on storage time: “There is no evidence to suggest that embryos are affected by the length of time they are frozen for.”

What India's ART Act says

On consent, section 22(2): “The clinics and banks shall not cryo-preserve any human embryos or gamete, without specific instructions and consent in writing from all the parties seeking assisted reproductive technology, in case of death or incapacity of any of the parties.”

On storage, section 28(2): “The gamete of a donor or embryo shall be stored for a period of not more than ten years and at the end of such period such gamete or embryo shall be allowed to perish or be donated to a research organisations registered under this Act for research purposes with the consent of the commissioning couple or individual”. Ask a clinic how it applies this to your embryos, and what it charges for storage each year.

Questions

Do all embryos survive freezing?

No. The HFEA says “Although most embryos do survive the freeze thaw process, some may not survive.”

How long can embryos be stored in India?

Section 28(2) of the ART Act says an embryo “shall be stored for a period of not more than ten years”.

Does freezing time matter?

The HFEA says “There is no evidence to suggest that embryos are affected by the length of time they are frozen for.”

Sources

• HFEA, Embryo freezing, read 25 September 2026.
• The Assisted Reproductive Technology (Regulation) Act, 2021 (No. 42 of 2021), read 25 September 2026.
• The Assisted Reproductive Technology (Regulation) Rules, 2022, G.S.R. 419(E), 7 June 2022, para 10.1 (not changed by the Amendment Rules, 2026, G.S.R. 491(E)), read 25 September 2026.
• Clinic data: each clinic's own website, as read by this directory; registry level from the National ART & Surrogacy Registry extract.