The birth of the country's first test-tube baby using a frozen egg, frozen sperm and frozen embryo is a major breakthrough, but doctors warn against unrealistic expectations.
Test-tube technology has fulfilled the dreams of millions of infertile couples to have a baby of their own. Since its introduction in China 18 years ago, this miracle continues.
Peking University Third Hospital, where the first Chinese test-tube baby was born on March 10, 1988, has once again amazed the public.
A test-tube baby, conceived through a frozen egg, frozen sperm and frozen embryo, was born on January 26.
The baby boy has made history, becoming China's first, and the world's second, "three-frozen" test-tube baby.
The "three-frozen" technology offers hope to women with cancer who can have their eggs frozen before going through chemo and radiotherapy.
All medical checks show the new baby in normal condition.
"Research on freezing egg is still at an initial stage, but is crucial to the whole reproduction technology," said Professor Chen Guian, a research fellow with the test-tube baby laboratory of Peking University Third Hospital.
"The technology needs to be further improved for a wider clinical application. We will do a long-term, follow-up evaluation of the baby's health condition."
The new technology, called egg vitrification, can freeze eggs for long periods.
However, compared to the sperm and embryo, eggs are much more fragile during the freezing and thawing process, and this can affect its later fertilization with the sperm. It also may create lifelong health risks for the newborns.
'Three-frozen' technology
So far, of more than one million test-tube babies in the world, just about 100 have been born through the eggs freezing technology, first tried in 1998.
According to Chen, this technology that allows women to freeze their eggs and use them at a later time to conceive a child, marks a tremendous advancement.
It is particularly aimed at women diagnosed with cancer but who have not yet begun chemo or radiotherapy that is toxic for the eggs.
As the technology becomes more mature and safe, it can offer an option for young women to preserve their future ability to have children.
"However, it is still not a responsible thing to do to establish an egg bank for the general public at present. More research is required," said Qiao Jie, director of the Reproductive Health and Fertility Center in the hospital.
The world's oldest test-tube baby is no more than 27 years old and the one in China, 18 years old. But assisted conception technology is developing very rapidly.
Initially, all that doctors could do was to put sperm and eggs together in a Petri dish to hope for the best.
Later, doctors learnt to fertilize an egg with a single sperm cell, applying a technique called intra cytoplasmic sperm injection.
Then, an even more exciting development took place genetic testing of embryos before being implanted. It mainly applied to couples with genetic diseases.
The doctors picked a cell from the embryos for an analysis of serious birth defects before placing the embryos in the uterus. However, only genetic diseases related to a single gene or chromosomes can be examined.
The most recent ovoplasm transplant technology is still at an experimental stage and is forbidden in most countries. This technology targets elderly women incapable of producing high-quality eggs. Scientists try to replace the ovoplasm in their eggs with that of the eggs of young women as this can significantly enhance the former's vitality.
"Though the ovoplasm contains only about 1 percent of the total genetic material, scientists are still not sure about the potential health risks for the test-tube babies or their later generations, considering that three persons' genetic substances are being integrated," Qiao said.
"Owing to variations between animals and humans in the genetic expressions of the next generation, these doubts cannot be resolved through animal tests," said Qiao.
With test-tube baby technology advancing rapidly and becoming a routine medical procedure, people are also becoming more positive towards test-tube babies and overcoming their initial reservations.
Just in Peking University Third Hospital, the number of test-tube procedures has increased to 1,000 every year from the initial few cases.
So far, the hospital has undertaken 8,000 test-tube procedures, of which a third have resulted in successful conceptions. Even though the expensive procedure cannot guarantee a baby, many couples consider it worth a try.
According to experts, the infertility rate among the general public has not increased significantly in recent years. But the faster pace of life is forcing more couples to put off having children, and this has led to an increase in the number of older infertile couples.
"Test-tube technology gives them another chance to have a baby. But we are not encouraging women to put off their conception for too long," said Qiao.
According to Qiao, the best time to have a baby is between the ages of 26-28, and the oldest age should not exceed 35.
"The risks of high blood pressure and diabetes increase with age during the gestation period," said Qiao.
In the test-tube procedure, several embryos are placed in the uterus to improve the success rate and hence, multiple births and preterm deliveries are much more common than in natural conception.
"Such babies may be exposed to more health risks in later life," said Qiao.
Doctors now implant fewer embryos to reduce the incidence of triplets and higher order multiples. But the rate of twins is still much higher among women going in for test-tube babies than under natural conception.
According to Qiao, the rate of congenital deformity among test-tube babies is about 2 per cent, similar to that among naturally conceived babies.
But she noted that data from follow-up studies on test-tube babies in later life is not complete owing to the non-co-operation of the parents.
So far, scientists the world over have found a slight increase in the risk of major birth defects in test-tube babies, such as heart or muscle and skeletal defects, compared to babies conceived naturally.
But whether the difference is a result of the medical procedure itself is still hotly debated.
(China Daily March 15, 2006)
