John Edwards’s defense team surprised a packed courtroom Wednesday by resting its case — after just three days — without calling Edwards or his former mistress to the stand, a decision that ensured that almost all the main characters in the 17-day drama remained offstage.

Jurors also never heard from Edwards’s daughter Cate or the wealthy patrons who prosecutors say funded the coverup in hopes of avoiding a scandal that would have killed Edwards’s presidential campaign and his later ambitions to be nominated for attorney general or as a Supreme Court justice. One of the donors, the heiress Rachel “Bunny” Mellon, is 101 and considered too old to testify; the other, Fred Baron, is dead.

The jurors also couldn’t hear from the woman whom defense attorneys say Edwards was covering up his affair to protect: his wife, Elizabeth Edwards, who died of cancer in 2010.

Instead, in the anticlimactic final day of defense testimony, the jury got a detailed report about former mistress Rielle Hunter’s medical history. After 17 days of testimony steeped in salacious private revelations, jurors now know how long Hunter’s menstrual cycles lasted.

That would be 28 days, with four-to-five-day periods, in case you’re wondering. This last tidbit was read to the jury Wednesday by Abbe Lowell, the lead attorney for Edwards, who is accused of violating campaign finance laws by allegedly failing to report $1 million spent to cover up his affair with Hunter.

The details about Hunter’s menstrual cycle are being used to establish a timeline about the conception of a child fathered by Edwards.

That child, Frances Quinn, was most likely conceived between May 25 and 28, 2007, according to a doctor’s analysis read to the jury by Lowell. Hunter learned of her pregnancy during a July 3, 2007, doctor’s visit, and there is no indication that she previously used a home pregnancy test, Lowell said.

The defense is trying to show that Hunter could not have known she was pregnant in May 2007, when prosecutors allege that Edwards and former campaign aide Andrew Young solicited money from Mellon.

The length of the menstrual cycle is important to them because they are using the dates of her May menstrual cycle to establish when her June menstrual cycle would have been expected to start. It is on that day — June 8 — that she first could have reasonably suspected she was pregnant. It’s a way to attempt to cast doubt on the prosecution’s claims about Edwards’s motivations to keep the pregnancy secret.

Edwards did not suspend his presidential campaign until the end of January 2008, six months later.

Prosecutors are expected to ­argue that the defense timeline is irrelevant because Edwards would have still been motivated to keep the affair secret even if Hunter had not been pregnant.

Courtroom obervers said Wednesday that the relative speediness of the defense’s case was a sign of confidence that Edwards’s side was likely to prevail. The prosecution presented nearly three weeks of evidence and testimony from a former Edwards aide and campaign advisers that painted Edwards as a frequent liar but showed no direct evidence that he intended to break federal campaign finance laws, according to legal experts quoted by the Associated Press.

A key element of the defense is Edwards’s claim that he and his aides consulted with lawyers, who said the money paid by Mellon and Baron did not need to be reported. After much speculation about their identities, Lowell said Wednesday that they were Baron, a wealthy trial lawyer; Baron’s wife, Lisa Blue; and David Kirby.

In a possible boon to the defense, Lowell was allowed to tell the jury that Young, the key prosecution witness and former Edwards aide, told government investigators that he was “concerned” that the payments constituted “excessive contributions” but that his concerns were alleviated after talking to Edwards and the three lawyers. It’s a key point, because prosecutors must prove that Edwards knowingly violated campaign finance law.

The defense rested after less than three days of testimony. Closing arguments are scheduled to begin Thursday morning, and jury deliberations are expected to start Friday. Then, after more than 30 witnesses and dozens of hours of testimony, all Edwards will be able to do is wait.