People who have surgery towards the end of the week are more likely to die than those who have procedures earlier on, researchers say.
A British Medical Journal report into non-emergency operations in England, suggests the overall risk of death from such planned procedures remains low.
But it shows "unacceptable" variation in survival rates through the week, a leading body of UK surgeons says.
Researchers from Imperial College London gathered data from all non-emergency surgery undertaken by the NHS in England in 2008-11.
Looking at some 4 million operations they found more than 27,000 deaths within a month of surgery, putting the average risk of death at 0.67%.
The researchers say they are concerned about the significant variation over the week, with the risk lowest for surgery carried out on Monday and then increasing with each subsequent day to peak at the weekend.
The paper shows people who have their operations on Friday are 44% more likely to die than those who have a procedure on Monday.
http://www.bbc.co.uk/news/health-22687599
F***ing hell, scary.