The twins have been growing together in their mother's womb for six months, but the life of one of them may soon be ended in order to save the other. Doctors at Prince of Wales Hospital are ready to terminate the life of a 26-week-old unborn twin, who is highly likely to have a severe congenital blood disease, to save the life of the mother and the other twin. A final test result confirming the condition will be ready a few days before the procedure goes ahead. By that time, the fetus will be more than 27 weeks old. The High Court granted an order on Christmas Eve allowing the hospital to perform the abortion. Hong Kong law does not allow abortion of a fetus older than 24 weeks. It is the first time in more than 10 years that the public hospital has had to seek a court order to abort a fetus beyond that age. The unborn twin in this case is likely to suffer from alpha thalassaemia, an inherited blood disorder causing the body to make fewer healthy red blood cells than normal. Babies with the disease cannot survive and a woman carrying a baby with it has a high risk of life-threatening hypertension and dysfunction in the liver and kidneys. The Hospital Authority said in its writ filed to the High Court on Christmas Eve that the selective termination was necessary to save the life of the woman and the healthy twin. The woman was referred by a private doctor to the hospital early this month. The hospital's chief of obstetrics and gynaecology, Dr Cheung Tak-hong, said the case was very rare and alpha thalassaemia could normally be diagnosed before 20 weeks. Associate consultant Dr Law Lai-wa said a drug would be injected into the fetus' heart to stop it. The mother would carry the dead fetus until the birth of the normal twin. Law said the case did not involve an ethical problem because a baby with the condition could not survive.