Nine women started the hunger strike last week to protest beatings and insults by the guards.
One of the women ended her hunger strike earlier after she was hospitalized due to her deteriorating health.
Earlier, the international media-rights group Reporters Without Borders urged the women to begin eating, fearing they could die.
Three of the women are journalists and online activists.
Jailed Iranian human rights lawyer Nasrin Sotoudeh continues her hunger strike in the same prison.
She stopped eating on October 31 after prison authorities banned her relatives from visiting.
Last month, Sotoudeh was awarded the European Parliament's Sakharov Prize for Freedom of Thought for 2012.
Jailed Iranian filmmaker Jafar Panahi also won the prize.