The husband of a Sudanese woman sentenced to death for converting to Christianity says he will appeal against the ruling.

Mariam Yahya Ibrahim Ishag had been ordered to abandon her newly adopted Christian faith and return to Islam.

She had also been charged with adultery for marrying a Christian man.

Her husband, Daniel Wani, was pronounced innocent but their marriage was revoked.

Ishag says she was born to a Sudanese Muslim father, who was absent, and raised by an Ethiopian Christian mother.

Wani was quoted as saying on Saturday he would appeal against the decision.

"I was considered innocent and the marriage revoked - the revoking of this marriage means that my son is no longer my son and the one coming is not my son too, will not be my son - so this innocence means nothing and I will appeal for myself and I will appeal for my wife," the Reuters news agency reported.

Wani said he feared for the health of his wife and their unborn son while she is kept in a prison cell.

"Martin [my son] and my wife, they are all in prison and she is pregnant - she could give birth at any time, from today to 1st of June, she may give birth. I am afraid that being in prison is dangerous for her so if they would allow me to take her to the hospital that she delivered Martin in - even if it was under the watch of security guards, I would be thankful."

Wani said he is a US citizen, but his pleas to the US embassy for help went unheeded.

"Considering I am an American citizen, I am disappointed with the American Embassy's position from the beginning of the whole case," he said.

"At the start of the issue, I reported it to them but they didn't take much interest, particularly the consulate. They said they didn't have time. In fact last time, they said they didn't care much about the case. They came late - they intervened when they saw the issue was getting press attention - but the intervention was late."

Muhammad al-Nour, the lawyer representing Ishag, said his client was under immense pressure.

"Of course, from the 11th - the conviction - to Thursday, there was great pressure. Pressure on Mariam, pressure on her defence team; there were calls saying that she must be returned, threats that there were missionary groups saying that if she was not returned 'you will pay the price' - I mean direct threats," he said.

Nour said his team were "proud as Muslims to be representing Mariam".

Western embassies and Sudanese activists have condemned what they said were human-rights abuses and called on the National Islamic Front-led government to respect freedom of faith.