On July 4, a girl born at New York University Hospital by vaginal delivery weighed in at 7 pounds 13 ounces. She looked like a perfectly lovely normal baby, and she is. She is also the future of fertility medicine. The infant, whose parents prefer to remain anonymous, was conceived with an egg that had been frozen and thawed before being fertilized. Only about 125 children in the world have been born from frozen eggs because until this year it was difficult to successfully thaw frozen eggs without destroying them.
But this child is no freak accident. Jamie Grifo, director of the Division of Reproductive Endocrinology at the New York University School of Medicine, and his associate Nicole Noyes have frozen and unfrozen the eggs of eight women. “Five patients had positive pregnancy tests,” Grifo says. “One patient has delivered; two have pregnancies that are ongoing. Those results are comparable to what we see in in vitro fertilization with fresh eggs.”
Each year, one in six couples in the United States—about 5 million people—have trouble conceiving and many seek help from fertility specialists. While freezing sperm and embryos has been standard practice for years, the ability to freeze and then successfully thaw unfertilized eggs has all but eluded specialists. In a sense it’s been the glittering prize of the field because it gives a woman heretofore unimaginable reproductive freedom. If a woman can freeze her eggs when she is young, she can then wait until she is ready to have her own genetic offspring—whether she’s 50, 60, or even older.
There is, of course, an ethical quandary associated with late-life parenthood: If the average life span for women is around 75, should a 60-year-old have a newborn who could be motherless by the time she’s 15? There is also the question of whether young women at their peak of health—in their twenties—will have the forethought and resources to bank their eggs. (Harvesting demands an invasive procedure as well as pricey drugs for ovarian stimulation.) On the other hand, egg freezing could prove to be a marvelous breakthrough for cancer survivors. They can freeze their eggs before treatment and still look forward to having their own genetic children, even if chemotherapy damages their ovaries.
The technology for freezing eggs has been available for years. But eggs contain a large percentage of water, and until very recently that posed a seemingly insurmountable problem. Thawing caused ice crystals to form and prevented meiosis, the cellular process during which an egg’s chromosomes split up from 46 to 23, to be united later with 23 chromosomes from a sperm cell. Only one in 100 frozen eggs were even viable, and a smaller proportion of those resulted in a live human being.
Now scientists seem to have conquered the problem of ice-crystal formation using two approaches. One method developed at McGill University in Montreal, called vitrification, involves freeze-drying: Eggs are plunged into liquid nitrogen and cooled at a rate of 36,000 degrees Fahrenheit per minute to 385°F below zero. When thawed, the eggs have a survival rate of about 90 percent. Another method, developed in the United States and Italy, exploits changes in the chemical composition of the solution the eggs are frozen in. The New York University School of Medicine has a grant to study both methods to see which results in the greatest quantity and quality of viable eggs.
The next child conceived from a frozen egg is due to be delivered in February. Given what this development means to women and their reproductive freedom, perhaps it is fitting that the pioneering baby born at New York University will celebrate her first birthday a few months later—on Independence Day.
Jamie Grifo is a professor of obstetrics and gynecology at the New York University School of Medicine and the director of the school’s Division of Reproductive Endocrinology. As a clinician, Grifo runs a fertility clinic with one of the highest success rates in the country. As a scientist, he is one of the pioneers of germinal-vesicle transfer, an assisted-reproduction technique involving the transfer of an egg nucleus into a healthy donor egg
What leaps in reproductive medicine do you see on the horizon?
G: Well, of course there’s egg freezing, which will have its greatest use as an insurance policy for women undergoing chemotherapy. They will soon be able to bank their eggs and use them when they have a partner or when their cancer is in remission. It’s too soon to tell if lots of women will actually end up using egg freezing to delay having families. But at least it gives them the possibility. Also critical: blastocyst transfer [allowing embryos to develop robustness in a lab for five days instead of the usual three before transfer back into the uterus]. When this becomes mainstream, it will allow us to put fewer embryos into the uterus, which will in turn reduce risky higher-order pregnancies. Genetic testing is not standard in in vitro fertilization [IVF], but one day it may be. Ideally we will achieve higher and higher rates of live births with transfers of single healthy blastocysts. And we may be able to prevent the pain of recurrent miscarriages from chromosomal abnormalities.
You’ve been working on a method of “boosting” older eggs called germinal-vesicle transfer. What is the advantage of that technique?
G: Germinal-vesicle transfer may, theoretically, solve the problem of aging eggs. With an egg where the cytoplasm surrounding a nucleus isn’t good, we can take the nucleus and transfer it into a healthy donor egg. But the method is currently banned in the United States.
You passed this technology on to Chinese scientists, who performed a human germinal-vesicle transfer. What happened?
G: The first time a germinal-vesicle transfer was attempted in China, there was a triplet pregnancy. The woman had the pregnancy reduced, then lost one twin at 18 weeks and one at 25 weeks. The losses were not related to the germinal-vesicle-transfer technique. How do I know? You never know 100 percent, but what happened was a recognized complication of multiple gestation. They looked at the fetuses and found them normal in every respect.
Given today’s political climate, what do you think will happen in the field of reproductive medicine?
G: Well, let me put it this way. If the environment today existed when IVF was started in 1978, we never would have had IVF. In the first two pregnancies with IVF, one was ectopic and one was a miscarriage. Our government would have stopped us right there. But IVF has resulted in a technology that is mainstream. Like IVF, the technologies we’re working on now are to help people with serious medical problems—not to create Frankensteins.
Would science be better off with Democrats in the White House?
G: I don’t know. I just don’t know. Democrats think you’re not smart enough to make your own decisions. They think they need to protect you from evil scientists. They will regulate everything that could possibly happen. Republicans, on the other hand, think regulation isn’t good, except when it comes to decisions people make in their bedrooms. Then it’s absolutely required.
Is the time when a human will be cloned closer than we think?
G: There are still many hurdles to be overcome before humans can be cloned successfully. But I’ve never completely understood the fear. Here’s the thing: Nature has already created clones. They’re called identical twins. Anyone who knows identical twins knows how different they can be; so many factors in the environment play a role in development. And if the clones grow up in a different time, a different place, they will likely be very different people.