Ebadi's call came in a joint appeal titled "A Race Against Death For Nasrin Sotoudeh" issued along with Jean-Francois Juilliard, the head of the media freedom group Reporters Without Borders, and Francois Cantier, head of the Lawyers Without Borders group.
Sotoudeh has been held at Tehran's Evin prison since early September on charges including "acting against national security" and cooperation with Ebadi's Defenders for Human Rights Center.
"Her struggle is our struggle," the appeal says. "The Iranian regime is trying to crush a voice that it fears. Its attempt to reduce Nasrin Sotoudeh to silence obliges us to take up the challenge of a race against death."
Today's appeal came amid reports that Sotoudeh has been transferred to the prison hospital due to her physical condition, which has been weakened by a third hunger strike.
Sotoudeh's husband, Reza Khandan, told RFE/RL's Radio Farda today he has not received any formal notification of her condition.
Khandan said that during his most recent telephone conversation with his wife, he could tell that she was extremely unwell.
"Her body could simply not have taken it after nine days of a dry hunger strike," he said.
Khandan says that he has not seen his wife since the last court session on November 28.
"We were able to have a cabin meeting [talking through a screen] with her before that on alternate Thursdays, but due to the religious holidays, we haven't been able to meet with her," he said.
Khandan says their two children -- Nima, a boy of 3, and Mehrave, a 12-year-old girl -- are not permitted a cabin meeting with their mother because of the possible psychological trauma.
Sotoudeh is to appear in court on December 27 on a new charge of violating Islamic standards of conduct by not wearing the hijab.