By Dr. Nivedita Vishwanath Adapa, Director and Consultant Reproductive Medicine (IVF) Manipal Hospital, Mysuru

World IVF Day is observed every year on July 25 to remember and acknowledge the contribution of IVF to the field of infertility. It also helps create public awareness of the progress made in the field of infertility and the various options available for treatment.

The world’s first IVF baby Louise Brown was born on 25th July 1978 in Manchester, England, to Lesley and Peter Brown. Her doctor, Dr. Patrick Steptoe and the embryologist Robert Edward had worked  for over a decade before achieving success.

IVF involves 3 stages

1. Controlled Ovarian Hyperstimulation (COH) of follicles with daily injectables.

2. Egg collection.

3. Embryo transfer either fresh or frozen.

One of the biggest progress in this field is cryopreservation or freezing of sperms, eggs and embryos. It revolutionised the field of IVF and improved the success of IVF multifold.

Freezing of embryos was first successfully attempted in 1983 by Alan Trounson. Since then, frozen embryo transfer has become an integral part of invitro fertilisation. Embryos are frozen at -196 °C in liquid nitrogen cryotanks on day three or day five. Freezing and thawing of embryos is a very efficient process and over 95% of frozen embryos survive this process.

The intended mother might be given estrogen pills to build up the uterine lining before receiving progesterone therapy to make the uterus receptive to the embryo. The frozen embryos are then thawed and transferred at either the day 3 or day 5 stage. No significant difference between the live birth rate with either frozen or fresh embryo transfer.

Why are embryos frozen?

OHSS (Ovarian hyperstimulation) is a complication that can occur during COH in some patients. The incidence of late OHSS can be reduced by freezing embryos and transferring them at a later stage once the ovaries have become normal.

Patients who have conceived their first child through IVF can freeze the extra embryos. These embryos can be used to conceive their second or third child at a later date, hence avoiding repeated egg collections.

Women who need to undergo surgery, radiation, or chemotherapy for cancer can freeze their eggs or embryos prior to their treatment for cancer.

Social freezing is another indication wherein women who wish to conceive at a later stage, either due to career commitments or due to a lack of a partner can freeze the  embryos or eggs, to be used at a later stage.

The duration of storage has no significant effect on clinical pregnancy, miscarriage, implantation or live birth rate. Therefore, although fresh embryo transfer is still routine, the freeze-all strategy has been widely adopted and applied in recent years. It has proven to be a safe procedure as well.

Freezing embryos raises regulatory and legal issues, such as ownership, consent, and disposal of unused embryos. Hence, it’s essential to discuss these risks with a fertility specialist before undergoing the procedure.

By understanding the importance and process of  embryo cryopreservation, individuals and couples can make informed decisions about their IVF journey and fertility options.