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Experts say scientific advances are allowing people to start families decades after embryos are frozen. Cavan Images/Getty Images
  • In October, a baby girl was born from an embryo that had been frozen for 27 years, a new record.
  • Experts say freezing techniques have become so advanced that how long an embryo is frozen should not affect the health of the mother or the baby.
  • They say embryos being used that have been frozen for decades will become more common in the future.

It’s a story that brings new meaning to the term “old soul.”

On Oct. 14, 1992, a few months after the summer Olympics were held in Barcelona and just weeks before Bill Clinton was elected president, an embryo was frozen.

In February 2020, just as the COVID-19 pandemic had begun to take hold, that embryo was thawed and transferred to the uterus of 28-year-old Tina Gibson, a Tennessee woman who had struggled to start a family with her husband, Ben.

On Oct. 26, 2020, along came Molly — a 6-pound, 13-ounce baby girl, who broke the record for longest frozen embryo to have resulted in the birth of a child.

The embryo that created her sister, Emma, the previous record holder, had been frozen for more than 24 for years.

And, just in case you’re having trouble keeping up, their mother was born around the time Molly’s embryo was frozen. So, technically they’re close in age.

Both baby girls were frozen together as embryos, which were then donated. Both girls are full genetic siblings.

Their unique story may prompt questions of how exactly this happened, but also what this means for the future generations of children, families, and embryos.

Healthline asked experts for their take and to explain what, if any, downsides there are to using embryos frozen that are decades old.

The process of in vitro fertilization (IVF) sometimes results in extra embryos, which are eggs that have been fertilized by sperm.

There are a number of things you can do with the extra embryos. One of them is embryo donation, usually done anonymously.

“Once an embryo is frozen, it stays at the same level of development forever,” Dr. Sigal Klipstein, FACOG, chair of the ethics committee for the American Society for Reproductive Medicine and director of the egg donor program at InVia Fertility in Chicago, told Healthline.

“For example, we sometimes have women who freeze embryos for their future use,” she said.

“She might have been 30 when she had her first baby and 40 when she had her second or third,” Klipstein said. “Those embryos that she made when she was 30 have the same risk of Down syndrome, risk of miscarriage of a woman who is 30, so they’re healthier, younger embryos.”

Every fertility clinic that works with donated embryos has its own way of managing how donation works.

“At University of Washington, we don’t let people designate. They can designate that they want the embryos sent to a particular person, but they can’t say I only want my embryos given to a heterosexual married couple, for example,” said Dr. Ginny Ryan, a professor and division chief of reproductive endocrinology and infertility at the University of Washington Medical Center.

“Other places, though, do allow you to designate that as such, or even [based on] race. We felt that that was discriminatory and not what we wanted to practice,” Ryan said.

There are many companies, she said, and each has a slightly different policy as to whether the originators of those embryos will be told the embryos are being used.

Generally speaking, the state of practice is to not inform them.

There are two cryopreservation techniques typically used to freeze embryos. They’re called slow freeze and vitrification.

“Slow freezing was done earlier in the world of freezing embryos and now it’s vitrification,” Ryan said. “Embryos with the slow freeze technique are less likely to survive the thaw.”

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Experts say frozen embryos can be stored in liquid nitrogen for decades. Provided by Reproductive Medicine Associates of Connecticut

A 2009 study found that vitrification provides “a higher survival rate of human embryos and minimal deleterious effects on post-warming embryo morphology.” That can improve clinical outcomes.

“[The Gibson embryo] was frozen and just left in sort of a deep freeze in liquid nitrogen for all those years,” Klipstein said. “So, someone was a good shepherd of that embryo.”

“My understanding is that [this couple] were at risk of having a baby with cystic fibrosis,” Klipstein said, “and so instead of trying to conceive on their own and risking having a baby with cystic fibrosis they chose to use a donor embryo.”

Other options would have been undergoing IVF and a process known as preimplantation genetic testing “to identify the embryos that do not carry this disease and transferring one of the unaffected embryos (statistically, half of the embryos should not have cystic fibrosis). They could also have chosen a sperm or egg donor who does not carry cystic fibrosis, or they could also opted to pursue adoption,” she added.

“Once the embryo is frozen, it can be frozen indefinitely. Same with sperm. Same with eggs,” Klipstein noted.

Whether the embryo is transferred back to the person who produced the egg, or as in the case of the Gibson children, to another person, the science has remained the same 27 years later.

Whether the embryo has been frozen for 1 year or 27 years, Klipstein noted that the science is the same. It can be thawed and transferred to the woman who created it or to someone else.

The preparation of the uterus is also the same, Klipstein said.

Before choosing a donated embryo, parents can learn about the characteristics of the embryo donors.

“If you can find a match for whatever characteristics are important to you in those embryos,” she said, “it’s a really nice thing to be able to do [for someone].”

The quality of the embryo being transferred is important, said Dr. Spencer Richlin, a board certified reproductive endocrinologist at Reproductive Medicine Associates of Connecticut, where he’s a partner and surgical director.

“Depending upon the quality of the embryo, we can have pregnancies with embryos that were frozen many years ago,” he said. “In general, embryos do not ‘mind’ being frozen, and their potential to become a pregnancy does not decline as a result of being frozen.”

“We don’t look at the length of time that an embryo is frozen to make decisions,” Klipstein told Healthline.

In fact, she added, in some cases an embryo frozen first may be chosen for transfer first.

“If a patient of mine, let’s say, has done two IVF cycles and happens to have embryos frozen from both of those cycles,” she said, “my preference would be to use the embryos from the first cycle, from the older cycle, because the female was younger at the time and the [embryos] would probably be a better quality.”

That is, “those embryos might be older but actually better,” Klipstein said.

Richlin said there are no downsides to using an embryo that has been frozen for many years.

“At the end of the day, if the embryo has 46 chromosomes, it has an excellent likelihood of implanting and going on to produce a pregnancy,” he said. “If by chance the embryo does not have 46 chromosomes, it will not implant or will end up as an early pregnancy loss.”

He said one of the advances in reproductive medicine is the ability to test or biopsy embryos before a transfer.

“The biopsy will tell us if the embryo is healthy for transfer or not. In addition, we can also biopsy embryos and tell if that embryo is likely to have a known medical condition,” he said. “This is called preimplantation genetic testing and has changed the way we take care of our patients.”

Richlin said that using an embryo as old as the one used in Molly Gibson’s birth should not have any impact on future generations.

“Based upon everything we have seen in our field to date, once an embryo results in a normal pregnancy, that baby is likely to grow up into a healthy adult who is able to conceive,” he said.

While she thinks the Gibson story is a positive one, Ryan told Healthline that the future health of a baby born from an embryo frozen for 27 years is still an unknown.

“I don’t mean to be alarmist, but I don’t think we know for sure that, even really that any embryo cryopreservation, let alone long-term embryo cryopreservation, has no harmful impacts,” she said.

“I think it’s a bit tricky to know because we just don’t have big numbers and long-term outcomes for those children,” said Ryan, who reiterated that “any sort of less visible issues, long-term health” is still an unknown.

“Now we’re starting to understand more about intergenerational problems, so fetal issues that might impact the fetus or the embryo that doesn’t then show itself until adulthood,” she said, “[like] increases in diabetes, increases in cancer risk.”

Ryan hopes there will be more research on the outcomes of children born from embryos frozen for long periods of time.

“Whether that’s the CDC [Centers for Disease Control and Prevention] or the Society for Assisted Reproductive Technologies, or somebody in the field is gathering the cases, again just to look for long-term outcomes of these prolonged freezes,” she said.

Dr. Kenan Omurtag, a reproductive endocrinologist and associate professor of medicine, obstetrics and gynecology at Washington University in St. Louis, agreed that not much is known about the future health of a baby born from an embryo as old as the one used in the birth of Molly Gibson.

“We only have a handful of reported births from embryos cryopreserved over 25 years,” he said. “Not enough [is known] to draw any conclusions about future health.”

Josephine Johnston, LLB, MBHL, a research scholar and director of research at The Hastings Center, a nonpartisan bioethics research institute in New York, agreed that more research would be beneficial.

“As a general matter it’d be helpful to have more long-term data on the health and other impacts of the use of reproductive technologies, including donor embryos,” she said.

Johnston said it’s important for people using frozen embryos to be informed.

“I think it is important to convey any known or proven health risks associated with the use of frozen embryos, and in particular whether there are any known risks associated with use of embryos frozen for a long time,” she added.

Klipstein cited several studies, including one from 2008, that found “cryostorage duration did not adversely affect post-thaw survival or pregnancy outcome in IVF or oocyte donation patients.”

“There is no evidence of long-term risk to children born from frozen embryos,” she said. “Two studies looking specifically at donated embryos showed that the length of time in storage did not have any adverse effects on pregnancy outcome.”

“There is no reason to believe that the length of time that embryos are frozen has an effect on long-term outcomes for the children that result from the transfer of these embryos,” Klipstein added.

Ryan thinks there should be a broader discussion about the protection of embryos frozen in storage.

In recent years, there have been stories about a growing number of embryos lingering in limbo at fertility clinics.

“How many embryos are out there in storage? There are thousands and thousands and thousands — how we take care of those embryos?” Ryan said. “How do we make sure that they don’t get lost because of poor identification or handoffs at clinics […] transitioning in leadership or shutting down?”

Keeping track of embryos becomes a practical issue for the private clinics and medical centers that house them, Ryan said.

“What are their responsibilities to those embryos? And how to reinsure that there [are] processes in place so that we can do the right thing by these embryos?” she said.

“I think a lot of patients go into their infertility care and their IVF care, and they’re just really focused on that initial outcome and not thinking so much about what is the appropriate thing to happen to these embryos that I’m making that I may never use,” Ryan said.

Counseling people in advance of infertility treatment about what’s going to happen to their embryos in the future, or even when they die, is a good practice, experts say.

Johnston said that we should expect to see more stories like the Gibsons’, especially given the number of embryos in frozen storage.

“As we move further and further ahead with IVF, we should expect that embryos frozen decades ago may be thawed and used in pregnancy attempts,” she told Healthline.

“This will be especially true going forward, as freezing methods have improved significantly and will result in sperm, embryos, and eggs being frozen for a long time and then used in successful IVF cycles,” she said.

Johnston thinks the story should give hope to people who undergo IVF, now or in the future, and “who are considering using frozen embryos.”

It’s hopeful to think “that even those embryos that have been frozen for a long time could still survive the thawing process and could lead to a healthy birth,” she said.

Omurtag said the Gibson story won’t be so rare in the coming years.

“Get used to this,” he said. “As more and more embryos are frozen, it will not be unusual for couples seeking embryo donation to use embryos that were stored in 2010 and to use them in 2040.”

“The technology to select and freeze embryos is better today than it was previously,” Omurtag said, “so I suspect as more embryos are donated, we are more likely to see these types of stories.”

Calling her daughter Emma — Molly’s sister — an “old soul” in a recent interview, Tina Gibson and her husband are delighted with the family they’ve formed through the National Embryo Donation Center in Knoxville, Tennessee.

Ryan was careful not to overemphasize the unknowns when it comes to babies born from older embryos and said there are positive takeaways here, including the aspect of the broad community coming together to help someone they don’t know build a family.

“I do think it’s also a pretty cool testament to technology and there’s a lot of positives,” she said.

“In the setting of people just willing to say, ‘OK, yeah, these embryos, whenever they’re used, I would love for them to help somebody else have a child,’” she said. “I really like this aspect of what we call third party reproduction for people to just put that out there in the world. Whether that’s used now or used 27 years down the road, I think that is really pretty cool.”