Bulletin Spring‧Summer Autumn‧Winter 1999

University Medical Researchers Make History University medical researchers have been making history recently. Significant breakthroughs have been achieved in cryopreservation (the deep freezing of embryos) and cholecystectomy techniques, resulting in Hong Kong's first birth from frozen embryos and Hong Kong's first successful laparoscopic cholecystectomy. These successes not only enhance the international prestige of the University, but most importantly, represent valuable contributions to medical science. As a result of pioneering work by doctors in The Chinese University in vitro fertilization (IVF ) programme, Hong Kong medical history was made on 24th May with the birth of twins produced from frozen embryos. The birth was Hong Kong's first from cryopreserved embryos. Cryopreservation, or embryo deep freezing, is already an accepted technique in other countries, and members of the Department of Obstetrics and Gynaecology and the Department o f Anatomy have been researching the process of cryopreservation since 1988. Perfecting high-technology techniques such as this offers hope for infertile couples who wish to have children. During I VF treatment for infertility, therapeutic stimulation of the ovary often produces a large number of oocytes. Such oocytes are collected using aspiration techniques, and many embryos can be produced after fertilization in the laboratory. To reduce the risk of multiple births, normally the I VF team implants no more than four embryos into the mother's uterus on each attempt. The rest have had to be discarded. The University's I VF team has been actively i nvo l ved i n research on methods of preserving these excess embryos at low temperature (cryopreservation) for a second attempt in case the initial I VF attempt fails to produce a pregnancy. According to Dr. Edward Loong Ping-leung, director of Chinese University's in vitro fertilization programme, another advantage of cryopreservation is that it allows doctors to select embryos of a better quality to be implanted at a most suitable time, although the success rate is usually only 10 to 15 per cent. The mother o f the recently bom twins had tried I V F six times before experiencing a successful pregnancy. In September 1989, 10 embryos were obtained during I VF but no pregnancy occurred after four of them were implanted in the mother, who had been unable to conceive for 10 years because of tubal blockage. The six unused embryos were frozen in liquid nitrogen, and four weeks later, after thawing, four were implanted, resulting in an ongoing twin pregnancy. Finally on 24th May a boy and a girl were bom six weeks prematurely by caesarian section at the Prince of Wales Hospital, the girl twin weighing 2.05 k logrammes and the boy 1.8 kilogrammes. The birth of twins came as a pleasant surprise because it was not expected that more than one of the four thawed embryos implanted in the mother's womb would survive. The success of Hong Kong's first birth from cryopreserved embryos is only the beginning, and Dr. Loong states that at present more than 100 women have registered with the University's I VF programme. s c i e n c e & me d i c i ne 10