Dr. Christiane Northrup in 2008. Evan Agostini/Associated Press

YARMOUTH — Instagram has blocked the account of Dr. Christiane Northrup, the retired Yarmouth gynecologist and bestselling author of health and wellness self-help books who has emerged as one of the country’s largest purveyors of COVID-19 vaccine conspiracy theories.

The move, which cuts Northrup off from her 175,500 Instagram followers, comes on the heels of a request by U.S. Sens. Amy Klobuchar, D-Minnesota, and Ben Ray Luján, D-New Mexico, that social media giants take action against Northrup and 11 other members of the so-called “disinformation dozen” who are responsible for spreading wild claims about COVID-19 vaccines and the pandemic.

The Center for Confronting Digital Hate in late March named her as one of the “disinformation dozen” who it said collectively generate 65 percent of all anti-COVID-19 vaccine social media shares and as much as 73 percent of those on Facebook, where her account is still active. Facebook owns Instagram.

“The social media companies need to explain why they continue to do business with these 12, because they profit from their interactions with these actors,” the center’s executive director, Imran Ahmed, told the Press Herald this week. “It’s outrageous to continue to do business with these people and benefit economically from what they are doing.”

Northrup, who rose to national prominence in the 1990s with the publication of “Women’s Bodies, Women’s Wisdom” and was a repeat guest on Oprah Winfrey’s top-rated television show, has used her social media accounts to deny the reality of the pandemic, to discourage the wearing of masks, and to argue that COVID-19 vaccines will make women infertile and cause recipients bodies to turn against them and then endanger unvaccinated people around them by the shedding malignant vaccine ingredients.

She has also falsely claimed the vaccines have ingredients that alter recipients’ DNA and will allow corporate entities to remotely monitor their biological states, a situation that would somehow benefit the Bill and Melinda Gates Foundation through the medium of cryptocurrency.

An analysis by The New York Times found Northrup played the key catalyzing role in the phenomenal spread of a viral 26-minute conspiracy video, “Plandemic,” after sharing it with her Facebook followers on May 5, 2020. The slickly produced video argued that a secret cabal of elites was using COVID-19 and the vaccines that would be developed to fight it to enrich and empower themselves.

“Her status as a celebrity doctor made her endorsement of ‘Plandemic’ powerful,” the New York Times reported May 20. “After Dr. Northrup shared the video, more than 1,000 people also shared it, many of them to groups that oppose mandatory vaccinations.”

Northrup has not responded to multiple interview requests from the Press Herald this week.

A Facebook spokesperson, Mark Ranneberger, provided a statement Thursday night that said the company had “updated our policies to take action against accounts that break our COVID-19 and vaccine rules – including by reducing their distribution or removing them from our platform – and have already taken action against some of the groups identified in the Center for Countering Digital Hate report.”

It was not clear why Northrup’s Facebook account – which has half a million followers – was not also disabled. Her Twitter account, which more than 113,000 people follow, also remains active, and that company did not respond to an interview request.

Northrup, who practiced obstetrics and gynecology in Portland and Yarmouth for 26 years, has not been licensed to practice medicine since 2015, when she allowed her medical license to lapse, state records show.