There was no physical evidence that Diana, Princess of Wales was pregnant, according to the British pathologist who examined her body.
The car carrying Diana was being pursued by photographers
Dr Robert Chapman, who carried out Diana's post-mortem, told her inquest that her womb and ovaries did not show the tell-tale signs of pregnancy.
But he said they would not necessarily be visible very soon after conception.
Meanwhile, the coroner has lost his bid to have testimony from paparazzi involved in the case read to the jury.
Lord Justice Scott Baker lodged an appeal on Friday challenging a High Court ruling which prevented the inclusion of statements from French photographers who pursued Diana on the night she died.
He had sought to include the written testimony after French authorities ruled they would not force the paparazzi to appear at the inquest in person.
But Lord Justice Waller, sitting with Lord Justice Dyson and Lord Justice Latham, said the appeal had been dismissed and the reasons for the decision would be given in a written judgment later.
The princess and Dodi Al Fayed died as a result of a car crash in a Paris tunnel on 31 August, 1997, along with their driver Henri Paul.
Opening the inquest in October, Lord Justice Scott Baker said any pregnancy was unlikely to "be proved one way or the other".
Then on Monday the jury at the High Court in London heard that Dr Chapman examined the bodies of Diana and Mr Al Fayed at Hammersmith and Fulham mortuary in west London on the evening after they died.
He told them he inspected Diana's womb and ovaries for signs of pregnancy as he would for any woman of child-bearing age.
The court heard those signs included a thickening in the wall of the uterus, the presence of an embryonic sac and changes to the appearance of the ovaries.
Dr Chapman said he would "expect" to see these when the embryo was three weeks old, but they could be visible as early as seven days after conception.
Nicholas Hilliard, counsel to the inquest, asked him: "Were any of these indications present here?"
He replied: "No."
Dr Chapman said his findings would have been "more complete" if he had taken a tissue sample from the princess's body.
But he said he was "very satisfied" that his visual examination was thorough enough to support his view that she was not pregnant.
The jury has heard that Mr Al Fayed's father, Mohamed, believes Diana and his son were murdered by the security services because she was pregnant.
He also claims Diana's body was deliberately embalmed in Paris to obscure the results of any pregnancy test that might have been conducted.
Lord Justice Scott Baker said he was "disappointed" to lose the appeal
Dr Chapman confirmed that fluids used in embalming could lead to some changes in a body, such as causing blood clots to form, but he said the chemicals would not obscure the physical evidence of a pregnancy if one existed.
He added that in his experience it was usual for bodies to be embalmed after repatriation not before.
As the pathologist began his evidence on Monday, two members of the public had to be ejected from the courtroom after interrupting proceedings by shouting about "the conspiracy".
Dr Chapman also told the hearing that tests showed Diana had not drunk any alcohol in the hours leading up to her death, although Mr Al Fayed had.
A statement on behalf of Lord Justice Scott Baker said he was "disappointed" to lose the appeal as the absence of paparazzi testimony was likely to prolong the inquest and increase costs.
"However, the coroner will do what he can to minimise these while taking such steps as he can to enable the jury to hear the evidence, in a manner consistent with the Court of Appeal's judgement," the statement said.
Meanwhile, one of the paparazzo witnesses to the crash has been summoned to give evidence on Tueday, it has been revealed.
Romauld Rat has been contacted by French officials and may appear via video link.
But it is unclear whether Mr Rat, who allegedly phoned the Sun newspaper from the crash scene demanding £300,000 for photos, will attend.