Fatemeh Bakhteri was initially handed a one-year sentence in September 2018 for "propaganda against the regime" together with a two year ban on social activities involving more than two people.
At the same ruling fellow Christian, Saheb Fadaie was sentenced to eighteen months imprisonment and two years' exile in Hamedan - in the north west of Iran for "action against national security through collusion and gathering."
At an appeal hearing on 15th January the pair were pressured by presiding judges Hassan Babaei and Mashallah Ahmadzadeh to renounce their faith.
After the pair refused to do so an appeal court ruled to uphold the sentences in a decision announced in May.
According to religious freedom charity Middle Eastern Concern (MEC), Fatemeh presented herself to officials at Evin Prison in Tehran to begin her sentence on 31st August.
MEC are encouraging Christians to join them in praying for Fatemeh.
Friends of Fatemeh report that she was not afraid as she went to prison on Saturday, but request prayer for her that the Lord would strengthen and encourage herself and her family, fellow Christian Saheb and all other Christian prisoners serving sentences in Evin Prison. Fatemeh also asked that Christians pray for the Iranian authorities to cease religious persecution and respect the law of freedom of religion.
Stay up to date with the latest news stories from a Christian perspective. Sign up to our daily newsletter and receive more stories like this straight to your inbox every morning.