Massachusetts mom Lindsay Clancy blankly stared in court Monday as she headed to trial for fatally strangling her three small children in an alleged postpartum psychotic state, new photos show.

The wheelchair-bound 35-year-old remained stoic, showing little emotion, as she looked down at one point and closed her eyes at another during jury selection in the sensational case in Plymouth.

The highly anticipated trial will hinge on whether jurors believe the killer mom — paralyzed from a later suicide attempt — was suffering from postpartum psychosis worsened by a cocktail of prescribed drugs when she committed her unthinkable alleged crime, experts said. 

“The whole case is just her state of mind and whether she was aware of right from wrong and literally if [she was aware] what she was doing was going to end up killing her kids,” former prosecutor Mark Bederow told The Post.

“Any juror is gonna wanna know why the hell would this woman do this? Why would a seemingly normal young woman living a beautiful life just murder her three children?”

Clancy is accused of using exercise bands to kill her young kids in the basement of the family’s Duxbury, Mass., home before becoming paralyzed from the waist down from a botched bid to kill herself Jan. 24, 2023.

Her lawyer, Kevin Reddington, has said he plans to ask the jury to find her not guilty by reason of insanity on the grounds she was suffering from severe postpartum psychosis and heard a voice telling her to carry out the heinous acts.

Legal experts said that key to her defense will be educating the jury, through medical witnesses, about the rare mental disease that allegedly led to the tragedy.

Clancy’s team will call medical experts to testify about postpartum psychosis, the treatment Clancy was receiving and the medications she was on — all in a bid to explain why she wasn’t in her right mind during the crimes and ultimately why she should be let off the hook, experts said.

Prosecutors will likely meanwhile call their own expert medical witnesses to argue that Clancy wasn’t suffering a mental break but rather was lucid enough to methodically plan how to get her husband out of the house that day so she could be alone with their children: Dawson, 3, Cora, 5, and 8-month-old Callan.

“It boils down to a battle of the experts,” former prosecutor Margaret McLean told The Post.

Bederow added that severe postpartum is “quite obviously a real thing and can lead seemingly normal people to do completely abnormal things.’’

Clancy and her husband, Patrick Clancy, have both filed lawsuits against the doctors who treated herm claiming they failed to diagnose her postpartum psychosis and bipolar disorder.

The docs also put her on a revolving door of powerful antipsychotic drugs and a “polypharmacy” of other psychiatric medications, the suits claim.

McLean said she thinks the defense strategy could raise enough reasonable doubt for jurors to either find her not guilty by reason of insanity or convict Clancy of a lesser included offense, such as involuntary manslaughter.

Clancy, a former labor and delivery nurse at Mass General Hospital, tried to kill herself by slicing her wrists and throat and throwing herself out of their home’s second-story window.

She is now a paraplegic and wheelchair-bound, which could also help to garner sympathy from jurors, McLean said.

“Here there is so much evidence showing that Lindsay Clancy sought help, and you’re going to have excellent experts come on to talk about what she was going through and the fact that she’s bound to a wheelchair,” McLean said. “I think that some people will have sympathy for her.”

But Bederow also noted that “it will take a great deal of humanity and compassion for jurors to get past the act itself and really focus on her mental state.”

Two advocates for perinatal mental health in women, who experienced severe postpartum reactions themselves, said they agree that Clancy probably had postpartum psychosis and that better awareness and treatment could have prevented the tragedy.

“The description of what happened with her is pretty much textbook,” said Teresa Twomey, a former lawyer and current mediator. 

“Essentially, whenever I see a story of a woman who is described pretty universally as a great mom, who then does something to harm somebody that is completely outside of her past behavior and what people describe as her nature, my assumption is psychosis.”

Paige Bellenbaum a social worker and perinatal-mental-health specialist, said “This is a woman who wanted nothing more than to be better.’

“For almost two years, She was trying so hard to get better, but when women don’t have access to specialty treatment providers … this is where mistakes can happen.”

Clancy’s trial is slated to last one to two months and could feature the testimony of up to 200 witnesses, including Patrick.

Judge William Sullivan has said there will be 18 jurors chosen, including alternates.

Dr. David Benjamin, a clinical pharmacologist and forensic toxicologist who is slated to testify on Clancy’s behalf, said, “This is one of the saddest cases I’ve ever been involved in.”

He said he doesn’t know why the doctors she was seeing at the same time were undermining each other by yanking Clancy off of certain meds and putting her on others without consulting each other.

“I’m going to take you off all of those meds and put you on these and you’ll do much better,” Benjamin said of her doctors’ apparent thoughts.

“And you know what happens? The person falls out of gear and commits a crime or hurts somebody because the stupid second doctor, their ego got in the way, and they changed what she was doing.”

“There’s this Macy’s versus Gimbels attitude among the docs,’’ he said, referring to the famous onetime business battle between the legendary department stores.

“Like, who’s the best doc in the world. And poor Mrs. Clancy is in the middle of it.”