NEW mothers are being asked to donate their babies' umbilical cords to a fledgling bank - the umbilical blood bank. The facility is the brainchild of the Hong Kong Marrow Match Foundation, and will collect placental material to extract blood needed by desperately-ill patients. The stem cells found in blood from the umbilical cord can help people with fatal blood diseases such as acute leukaemia, lymphoma and aplastic anaemia, mimicking the effect of a bone marrow transplant. The foundation plans to experiment with the idea at two hospitals - the Queen Mary and Queen Elizabeth - after March. Foundation honorary secretary Dr Raymond Liang Hin-suen said mothers would be asked for their permission before placenta - which would otherwise be dumped - was used to extract umbilical cord blood. In initial trials, several hundred blood samples would be stored at the Red Cross centre at minus 150 degrees Celsius, where they could be kept fresh indefinitely, Dr Liang said. 'Umbilical cord blood transplants have advantages over bone marrow transplants such as less rejection and a shorter recovery period,' he said. 'But its major limitation is it doesn't contain a concentration of stem cells high enough for a patient weighing more than 40 kilograms. 'This provides an alternative to a bone marrow transplant. But it doesn't mean it can replace bone marrow transplants or that we don't need bone marrow donors anymore,' Dr Liang said. The Queen Mary Hospital carried out its first umbilical cord blood transplant from one sibling to another last April. Umbilical cord blood transplants from unrelated donors have never been performed in Hong Kong. The foundation named actor-singer Andy Lau Tak-wah yesterday as its bone marrow ambassador.