Maryam Naghash Zargaran is being blocked access to treatment for long standing health problems as the prosecutor's office is refusing to allow her to leave prison.
She's currently serving a four year sentence, which began in July 2013, for her work on an orphanage with former Christian prisoner Saeed Abedini (pictured). She was charged with "acting against national security".
The Muslim convert has a history of heart problems and is said to be suffering with pain in her ears and severe headaches but the authorities at Evin Prison in Tehran are reportedly not recognising the severity of her condition.
She's now gone on hunger strike refusing solids and liquids with her family said to be very concerned for her.
It's reported that her fellow prisoners showed their support by forgoing family visits on the weekend as a form of protest.
Charity Middle East Concern is calling for prayer that: "The Prosecutor will relent and allow Maryam to go to hospital to receive proper treatment. That the Lord will sustain Maryam and her family and friends during this critical time. That Maryam will be released from prison soon and God will heal and restore Maryam. And that God will move the Iranian authorities and officials to love mercy and act justly."
Saeed Abedini, was released from prison as part of a deal with the USA announced by President Obama in January.
Many Christians remain in prison facing similar charges.
Those who convert from Islam to Christianity in Iran face many difficulties.