In what may be the first such case in the United States, a Georgia woman gave birth after being implanted with eggs that had been frozen.
Up to now, U.S. doctors have been able to produce pregnancies from frozen embryos - that is, eggs fertilized with sperm and then frozen - but eggs alone were considered too fragile to freeze.
The latest feat, which has been achieved only sporadically elsewhere around the world, could give women new reproductive options and sidestep some of the ethical objections to test-tube fertilization.
“This stretches the reproductive field as far as you can envision it right now,” said Dr. Joe Massey, co-founder of Reproductive Biology Associates, the Atlanta clinic that accomplished the feat. In 1993, the same clinic produced the first U.S. baby using sperm injected directly into a woman’s egg.
In 1986, a doctor in Australia was able to produce the first known births from frozen eggs. A year later, a team of German doctors also produced frozen-egg pregnancies. But until now, U.S. doctors have not been able to mimic the results, said Michael Tucker, scientific director of the Atlanta clinic.
“This is an area in our field in which no one has been able to reliably achieve results over the past decade,” said Dr. Anne Namnoum, director of in vitro fertilization at Emory University’s Center for Reproductive Medicine. “This is a significant development.”
The 39-year-old woman came to the clinic almost a year ago suffering from premature ovarian failure, which caused her to go through menopause early.
She had tried in vitro fertilization, where eggs taken from a woman’s ovaries are fertilized with sperm in the lab and the resulting embryo is implanted in the woman’s uterus. But it didn’t work because her husband’s sperm were too weak.
The clinic had been running a donor program for frozen eggs as part of its research since 1994. It successfully produced two earlier pregnancies using those eggs, but both ended in miscarriage. The clinic decided to use frozen eggs from a 29-year-old donor to try to help the 39-year-old woman.
Doctors thawed 23 eggs, 16 of which survived. All were injected with a single sperm from the woman’s husband. Then, four of the 11 that developed into embryos were implanted into the woman.
The result was doubly good: She had twin boys in August.
“They told me they had not had any success with it before, but I didn’t care. I wanted to get pregnant,” said the woman, who asked to remain anonymous. “Then when I gave birth, they told me I made history.”
Before freezing the donor’s eggs, the researchers came up with a chemical solution to soak the eggs in to mimic the follicle, the protective capsule that forms around eggs inside a woman. Eggs become separated from the follicle when they are removed from a woman.
The researchers also took out the water from the eggs and substituted a protectant to prevent ice from forming and destroying the internal parts.
They used a special freezer that could be programmed to bring down the temperature slowly. Finally, the frozen eggs were placed in liquid nitrogen. Before being fertilized, the eggs were thawed just as slowly.
“Before this, nothing had worked consistently,” Tucker said. “I am confident I can reproduce this formula.”