Mohammadi, 53, was urgently transferred from prison to a hospital in northwestern Iran on May 1 after losing consciousness. Nearly 10 days later, a court granted her release on bail, and she was moved to a hospital in Tehran where her specialists could examine her, according to her foundation.

The angiography there showed two of her main arteries had significant blockage, and doctors concluded her vascular disease had “significantly deteriorated” since her last such procedure in 2024, the foundation said. The attending physician reported that her blood pressure continues to fluctuate, in part because of damage to a part of the brain responsible for regulation. The doctors recommended an eight-month treatment course in an environment “free from external stressors, where she can receive permanent care and long-term treatment.”

Mohammadi won the Nobel Peace Prize in 2023 while imprisoned, recognized for her decades-long fight against the oppression of women in Iran and for the promotion of human rights. Her latest imprisonment began in December when she was arrested in the northeastern city of Mashhad.

Her family has said her health deteriorated steadily in prison, in part because she was beaten heavily during her arrest. She suffered a heart attack in March and has a blood clot in her lung that requires blood thinners and monitoring.

Her foundation and dozens of other Nobel laureates have called for her immediate and unconditional release. The health crisis has drawn renewed international attention to the treatment of political prisoners in Iran.