First frozen egg babies born by May
China's first test-tube baby using frozen eggs is expected to be born in mid-May, according to officials with the First Hospital affiliated with Peking University.
And the hospital that conducted the operation is also considering whether to set up an oocyte or egg bank in Beijing.
Li Xiaohong, director of the Reproduction and Genetics Centre at the hospital said the ground-breaking operation included freezing human eggs, thawing them, fertilizing them with sperm, and then implanting the eggs in a woman patient's uterus.
So far, six women have became pregnant through such operations at the hospital, Li said, adding that two of them are set to give birth in May.
One of the two expectant mothers should deliver twins if all goes as planned, the doctor said.
For years, scientists have been able to thaw frozen sperm and, more recently, have reported success at thawing frozen human embryos. But finding a way to freeze and thaw a woman's eggs has been rare.
Less than 100 women around the world have been able to become pregnant by using frozen eggs, said Li.
The problem has been that tiny human eggs are still much larger with much more water present than sperm or embryonic cells.
As a result, there's much more risk of crucial chromosome-laden fibers within the eggs suffering destruction from frozen water crystals.
Li said her centre had a 96 per cent egg survival rate after the thawing-out process, a surprisingly good record compared to the rest of the world. And the thawed eggs enjoy almost the same fertilization rate as fresh ones.
But she admitted the average survival rate may be lower since the technology differs from hospital to hospital and the condition of the eggs can vary from woman to woman.
She said the concept of egg freezing can have far-reaching influence on how and when people choose to become parents, with the technology beneficial to more than just infertile couples.
Young women who have not found their ideal husband or want to spend more time building a career will now be able to set aside eggs and make a decision to have a child years down the line.
Young women diagnosed with cancer might gain an option for having children later in life instead of simply accepting becoming infertile from radiation or chemotherapy treatments.
"The prospect of an egg bank is very bright since it could allow women to preserve their eggs," said Li.
Although the doctor refused to reveal the fee for egg preservation, experts estimate the charge is not likely cheap.
In Argentina, the price for preserving eggs is about US$830 a year per woman, a relatively expensive fee for a middle-income person in a developing country.
Li said the management of eggs is very important for an egg bank since the concept of egg freezing throws new wrinkles into the "right-to-life" debate.
"All the operations need to be done within the scope allowed by laws and regulations," said Li.
Meanwhile, much more study is needed before egg freezing becomes routine, she noted.
The success of using frozen eggs to make embryos is just a preliminary step and a great deal needs to be done to confirm the procedure is effective and safe, said Li.
While no birth defects or chromosomal abnormalities have been detected to date worldwide, it will take time to make certain the process is completely safe, said the doctor.