Ennis-Hill was provisionally named in the Great Britain squad on Tuesday for the competition in Moscow from August 10-18, despite struggling with an Achilles problem.
But she said in a British Athletics statement: “Up until now, we have been focusing on managing the pain so I can train and get myself in shape to go out there to win in Moscow — which has meant not focusing on finding a cure for the injury.
“The time has come now to stop chasing fitness and look to cure the problem.”
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