Italian investigative journalist Emiliano Fittipaldi, on trial with colleague Gianluigi Nuzzi after publishing books based on secret Vatican papers, told the press the judges had retired to deliberate and a verdict was
expected at 4:00 pm (1400 GMT).
Three other people - a Spanish Vatican official, his assistant and an Italian communications consultant - have joined them in the dock since November.
The scandal, the second to hit the Vatican, rocked the Roman Catholic Church with its leaked accounts of theft and greed, along with publication of secret recordings of Pope Francis's private conversations.
It then ballooned into steamier fare, as Spanish monsignor Lucio Vallejo Balda and PR expert Francesca Chaouqui turned on each other in the witness box.
Details emerged of alleged sexual affairs, glitzy parties and secret plots in the corridors of power.
Chaouqui, who had been involved in a review of Vatican finances and is accused of both "inspiring" and being ultimately responsibility for the leaks, was the only one to address the court Thursday.
The prosecution has called for a sentence of three years and nine months for Chaouqui, who along with the three other Italian nationals may be subject to an extradition request from the Vatican state in the case of a guilty verdict.
Chaouqui, who gave birth three weeks ago, said Thursday she feared the Vatican would ask Italy to clap her behind bars.
"If the court asks Italy to carry out the sentence, my son and I will spend the first years of his life behind bars," she told the court.
Fighting to hold back tears, she apologised to the judges for her someone erratic behaviour during the trial, but also complained about the prosecution's bid to give her the heaviest prison sentence, saying it was "as if I had acted alone".
Vallejo Balda admitted to leaking the classified papers but said he had done so under pressure from Chaouqui, with whom he claimed to have a "compromising" relationship. The PR consultant had allegedly threatened to "destroy" him.
He also claimed he had been blackmailed by a woman he believed to have links to Italian secret services and other contacts in a "dangerous world".
The trial has provoked outrage among campaigners for press freedom.
In closing statements on Wednesday, prosecutors rebutted accusations that the tiny city-state was attacking the media's freedom. Earlier this week they called for Nuzzi to be handed a one-year suspended sentence.
But Nuzzi's defence team insisted the journalist was merely "an Italian citizen who exercised the freedom of the press on Italian soil without endangering the peace and security of the Vatican".
Fittipaldi, who prosecutors said should be acquitted due to a lack of evidence, also defended his "right to inform" the public.
All five accused have been prosecuted under draconian anti-leaks legislation, which could have seen them face prison terms of between four and eight years.
The law was rushed onto the Vatican statute book in 2013 as a result of the fallout from the first Vatileaks scandal, which centred on secrets divulged by the butler of now-retired Pope Benedict XVI.