Emma Wren Gibson came into the world a record breaker. This adorable infant girl arrived via natural delivery on November 25, an incredible 24 years after being frozen as an embryo—the longest-frozen embryo to ever successfully come to birth, fertility doctors believe.
And get this: The embryo was frozen when Emma’s mom, Tina Gibson, was just one year old, People reported. “Do you realize I’m only 25? This embryo and I could have been best friends,” Gibson told CNN.
According to the National Embryo Donation Center, the Tennessee facility where the embryo was thawed and transferred to Tina’s uterus, Emma was born a healthy 6 pounds, 8 ounces, and she measured in at 20 inches long.
But wait, 24 years?! How is that even possible? Health asked Thomas Molinaro, MD, an ob-gyn and reproductive endocrinologist at Reproductive Medical Associates of New Jersey, to explain what embryo freezing involves and if Emma’s amazing story foretells a future where babies born from embryos frozen decades earlier will be routine.
No one knows how long a frozen embryo can last
Embryos—or eggs fertilized by sperm—are frozen to keep them in a “suspended state,” says Dr. Molinaro, so they don’t grow or age. They’re then kept cold in liquid nitrogen and stored.
Typically, the frozen embryos are used as soon as possible by the parents who created them, transferred into the womb within a few years, says Dr. Molinaro, who is also a clinical assistant professor in the department of obstetrics, gynecology, and reproductive science at Rutgers-Robert Wood Johnson Medical School. While it’s not known how many babies began as embryos frozen many years before being transferred into the uterus, clearly, it’s possible.
“No upper limit seems to be known,” he says, referring to how long an embryo can remain frozen. “Twenty-four is the oldest embryo I’ve heard of, but it doesn’t surprise me that it would still be viable.” Previously, the oldest embryo to result in a birth was thought to have been 20 years old, Time reported.
“Our experience in terms of babies born from frozen embryos is very reassuring,” Dr. Molinaro says. “There doesn’t seem to be any difference in the health of the child.” If an embryo is going to thrive, he says, a couple and their doctor will learn that pretty early on in the process. Should something be wrong with the embryo, the pregnancy probably wouldn’t take.
Frozen embryo success rates are hard to estimate
Many factors are taken into account in predicting a couple’s chances of delivering a healthy baby from a frozen embryo, explains Dr. Molinaro. “The stage at which the embryo was frozen, the technique by which it was frozen, and ultimately the age of the woman at the time that it was frozen” all play a role, he says, noting that fertility treatments in general have improved dramatically over the last couple of decades. For women under the age of 35, IVF cycles result in live births up to 43% of the time, according to the American Pregnancy Association.
When a couple is ready to use a frozen embryo, a specialist thaws the fertilized egg, warming it slowly and rehydrating it, Dr. Molinaro explains. “There are a series of steps to re-expand the embryo, but experienced embryologists can do that in less than hour.” Then the embryo is inserted into a woman’s uterus and develops, just like with any pregnancy.
RELATED: 5 Myths About Egg Freezing
Frozen embryos can be donated—and adopted
Since Tina Gibson, now 26, was a year old at the time of the embryo freezing, Emma is obviously not a product of the Gibson’s genetic material. Instead, she comes from what’s called embryo donation or embryo adoption. The process has become more popular in recent years, Dr. Molinaro says, and is the result of couples having embryos leftover after fertility treatments.
There are a few options for what to do with these leftover embryos: Discard them, donate them to research, or donate them to another couple who, for whatever reason, can’t produce a viable embryo on their own. Roughly 1,000 embryo donations occur in the U.S. each year, Health previously reported, and websites exist that match couples looking to donate and adopt fertilized eggs, Dr. Molinaro says.
To get our top stories delivered to your inbox, sign up for the Healthy Living newsletter
Embryo adoption has resulted in more than 7,000 births, Time reported, and most happen relatively quickly—unlike Emma’s 24-year journey, Dr. Molinaro says. “For us, demand for donated embryos is greater than the supply. When we have embryos available, we usually don’t have a tough time matching them.”
This article originally appeared on Health.com.