Scientists Have Discovered a New Set of Blood Groups
The unborn baby was in trouble. Its mother's doctors, at a UK hospital, knew there was something wrong with the fetus's blood, so they decided to perform an emergency C-section many weeks before the baby was due. But despite this, and subsequent blood transfusions, the baby suffered a brain hemorrhage with devastating consequences.
https://www.wired.com/story/new-blood-types/