The woman who drunkenly fell to her death down her luxury Union Square building’s trash chute was in the middle of a contentious divorce — and forced to undergo regular drug and alcohol tests, her lawyer told The Post on Thursday.

Lara Prychodko, 48, and her construction-boss husband were battling over homes in Southampton, an apartment in Chelsea and a residence in Williamsburg, among other assets, when she died.

She had already lost custody of her son, attorney Eric A. Seiff said, and was required to undergo drug and alcohol testing as part of the settlement.

“So here you have two parents with different points of view seeking a common result, which is a settlement, so one party gives here and the other party gives there,” Seiff said.

He said she had a 2012 conviction for driving while intoxicated and had been battling a drinking issue brought on by a “growing brain tumor.”

“I know she was absolutely convinced the pain and dependency she was experiencing that had her drinking was directly related to the growing brain tumor,” Seiff said.

He would not discuss her health at the time of her death, but said he spoke with her Monday and she sounded “upbeat.”

Multiple sources at the Union Square apartment building where Prychodko was found and what Seiff said was the couple’s primary marital residence on 10th Avenue in Chelsea said they also believed Prychodko was suffering from health issues.

Seiff said his client — who cops believe was intoxicated when she fell 27 floors to her death — had turned her life around and regularly passed “professionally monitored” drug and alcohol tests.

“I have not been aware of a single test that she failed the last year. For the last six months [the tests] have been professionally supervised,” Seiff said.

He said Prychodko and David Christopher Schlachet were in mediation that had been postponed for a month.

“I’m kind of uncomfortable talking about the litigation, as difficult and contentious as it was,” he said. “There is a young child, a father and an estranged husband who must be going through their own turmoil.”

Schlachet could not be reached; neither could Prychodko’s family.

A friend of Prychodko’s, who was seen crying at an apartment building on East 16th Street, less than two blocks from the Zeckendorf Towers, told a Post reporter she was “fiercely loyal” and “fantastic.”

“She was just starting to get back into work,” said the friend, who did not want to reveal her name. “She was a great mom. She loved her son.”

Additional reporting by Stephanie Pagones