The experimental cocktail of drugs developed by Regeneron Pharmaceuticals relied on fetal cells from an abortion in the Netherlands in the 1970s, according to the MIT Technology Review.
Mr Trump received the treatment after he was taken to Walter Reed over the weekend, before he returned to the White House on Monday evening.
The Covid-19 fighting Regeneron antibodies are actually made in cells from a hamster’s ovary, not human cells, according to the company.
But the firm used cells originally from a foetus in another way to produce the drug, the report states.
“According to Regeneron, laboratory tests used to assess the potency of its antibodies employed a standardized supply of cells called HEK 293T, whose origin was kidney tissue from an abortion in the Netherlands in the 1970s,” it states.
“Since then, the 293T cells have been ‘immortalized’, meaning they keep dividing in the lab, somewhat like a cancer, and have undergone other genetic changes and additions.”
The article states that Regeneron uses the 293T cells to make “pseudo-particles” of the virus that contain the infamous “spike” protein of coronavirus.
The company then uses that to test how well their antibodies will fight the virus.
Regeneron says that because the cells were acquired so long ago they are no longer considered related to the abortion.
“It’s how you want to parse it,” Regeneron spokesperson Alexandra Bowie told the magazine.
“But the 293T cell lines available today are not considered foetal tissue, and we did not otherwise use foetal tissue."
Ms Bowie told the New York Times: “293Ts were used in testing the antibodies’ ability to neutralize the virus. They weren’t used in any other way, and foetal tissue was not used in the research.”
The irony of the situation was not lost on the MIT Technology Review.
“When the president faced a deadly encounter with Covid-19, his administration raised no objections over the fact that the new drugs also relied on foetal cells, and anti-abortion campaigners were silent too,” it stated.
“Most likely, their hypocrisy was unwitting.
“Many types of medical and vaccine research employ supplies of cells originally acquired from abortion tissue.
“It would have taken an expert to realize that was the case with Trump’s treatment.”
On his first morning back in the White House, Mr Trump raised the issue of abortion which is increasingly becoming a talking point in the campaign, on Twitter.
“Biden and Democrats just clarified the fact that they are fully in favor of (very) LATE TERM ABORTION, right up until the time of birth, and beyond - which would be execution. Biden even endorsed the Governor of Virginia, who stated this clearly for all to hear,” Mr Trump wrote before adding: “GET OUT & VOTE!!!”, the president wrote.
It came after Joe Biden said he would make Roe v Wade the ‘law of the land’.
Regeneron did not respond directly for comment.