By Caitlin Painter

In October 1992, an embryo was frozen by an anonymous couple. It remained frozen for over 27 years until thawed by the National Embryo Donation Centre (NEDC) in Knoxville, Tennessee, and transferred into the uterus of a woman unable to conceive naturally. Born in October 2020, Molly Gibson is believed to hold the record for the longest frozen embryo to result in a birth.

The embryo remained frozen for over 27 years until thawed

Embryo freezing has been practised since the early 1980s, but it was initially unclear how long they could be frozen. The typical duration is 10 years, but as proven by Molly Gibson, decadesold embryos can still lead to successful births. The majority of stored embryos that can be adopted have been donated by individuals who have undergone in vitro fertilisation (IVF), after a successful implantation.

IVF is a popular technique available to help people with fertility problems become pregnant. After hormone treatments, a womans eggs are collected and fertilised, and the highest quality embryos can then be implanted, with unused ones typically frozen for further IVF attempts.

As proven by Molly Gibson, decades-old embryos can lead to successful births

A standard freezing process involves replacing water in the cells with a cryoprotectant, and then freezing the embryo extremely quickly to temperatures around -200C (known as vitrification) to prevent ice crystals forming. However, IVF creates a surplus of embryos, and the parent(s) have the decision of what becomes of them. Many choose to discard them. Some are donated for research and training purposes, whilst others are stored for embryo adoptions.

Dr Fiona MacCallum of the University of Warwick believes that the term embryo adoption is misleading, arguing that viewing embryo donations akin to adoptions could shift the public perspective of embryos more towards personhood status.

Dr Fiona MacCallum believes the term embryo adoption is misleading

This could have a great impact on stem cell research, where embryos are frequently used and subsequently destroyed. With this attitude, there is the possibility that embryos could undergo pre-implantation genetic screening. This is currently applied to check an embryo for specific genetic conditions, but could be misused to determine the future characteristics of the child.

Under the Human Fertilisation and Embryology Act of 2008, it is illegal in the UK to select the sex of embryos for non-medical purposes, whether during IVF with a persons own embryos or adopting them. It is common, however, for prospective parents to choose donated embryos of the same ethnicity as themselves, as well as from donor parents they share features with. It was only after they had chosen their desired embryos that Molly Gibsons parents discovered when they had been frozen.

Embryo freezing is the most effective way to preserve fertility, more than freezing eggs

For parents who are unable to conceive, embryo donations provide the opportunity of experiencing pregnancy and birth, with a 75% success rate of donated embryos surviving thawing and transferring. Of these embryos, 25 to 30% are implanted successfully, according to the NEDC.

Embryo freezing is also used by women about to undergo cancer treatments that may result in infertility, but who want a child afterwards. The UKs Human Fertilisation and Embryonic Authority evidences that embryo freezing is the most effective way for women to preserve fertility, more so than freezing eggs. Hence some women choose to freeze their fertilised eggs to increase their chances of a successful pregnancy later in life.

Older mothers are at a much greater risk of complications during pregnancy

Women may choose to postpone pregnancy until they feel more secure in their job and personal life, and having the means to do this has significantly increased womens reproductive freedom. A womans fertility decreases naturally with age, however, the advances in fertility treatments mean its increasingly common for older women to become pregnant. Despite this, older mothers are at a much greater risk of complications during pregnancy, prompting the discussion of whether those who otherwise would not be able to conceive and safely carry a baby should, just because it is scientifically viable.

Conversely, reproductive rights defined by the World Health Organisation (WHO) state that everyone has the right to decide freely and responsibly the number, spacing and timing of their children and to have the information and means to do so. For most cases, there is a 10- year limit on freezing embryos, leaving people with a difficult decision once this time is up: destroying their embryos or beginning fertility treatment.

For some, 10 years later is still too soon to have a child. If we know embryos can survive for at least 27 years, why is this arbitrary limit still imposed? Does it really increase womens reproductive freedom as much as we think? Despite this, fertility Science & Technology treatments are life-changing, and the law rightly allows infertile couples and individuals the chance of having a family with their own or donated embryos. These treatments also provide the chance for same-sex couples to have children through means other than adopting, by using donated embryos or donated eggs/sperm. In December 2020, a 61-year-old gave birth to her own granddaughter by acting as a surrogate for her son and his husband.

A 61-year-old gave birth to her own granddaughter by acting as surrogate

The scientific advancements made during the last 40 years regarding fertility treatments have given many parents the chance of having a child. The record-breaking case of Molly Gibson has highlighted the prevalence and importance of these treatments being a possibility in todays society, meaning embryo adoption could become much more popular.

Image: Amber Conway

Excerpt from:
Embryo freezing is revolutionary for those who can't conceive - Palatinate