Indian-born Saldanha, 46, was discovered hanging in her hospital lodgings in London, days after she answered the hoax call from DJs Mel Greig and Michael Christian at Australian radio station 2Day FM.
She put the call through to a colleague who disclosed details of the Duchess of Cambridge's condition during treatment for an extreme form of morning sickness in the early stages of pregnancy.
The nurse's subsequent death provoked widespread anger and British police launched an investigation to see if any offences had been committed.
"We have concluded that there is no evidence to support a charge of manslaughter," said Malcolm McHaffie, Deputy Head of Special Crime at the Crown Prosecution Service. Other possible charges would also not be in the public interest, he added.
Australia's media regulator has also launched an investigation into what happened, while Southern Cross Austereo, parent company of the radio station, apologised and promised to donate advertising revenue to a fund for the family of Saldanha.