MP Helena Guergis resigned from Prime Minister Stephen Harper's cabinet in April. ((Sean Kilpatrick/Canadian Press))

Rahim Jaffer has disclosed his wife, MP Helena Guergis, is pregnant in a letter explaining his absence from a parliamentary committee looking into illegal lobbying allegations against him.

Jaffer, a former Conservative MP, wrote in a letter to the government operations committee that he regrets defying a parliamentary summons to appear before MPs in Ottawa on Wednesday, but had to be at his wife's side as she underwent medical tests.

"Helena and I have been trying to have a child for some time," he wrote. "She has just completed the first trimester of a high risk pregnancy. Today I was with my wife, as I should have been, when tests were conducted to ascertain the health of our baby."

Jaffer said he and his wife are relieved to hear the test results were "good and there are no significant concerns right now about the baby's health." But he added the couple is "drained," and he hit out at the "considerable stress" Guergis has been under "as a result of her treatment by the prime minister and others."

Jaffer has denied he lobbied former colleagues in government for access to a federal green infrastructure fund, but admitted in a statement earlier this week that he inadvertently gave "incomplete" information during his last appearance before the committee in April.

After his failure to appear Wednesday, the committee called on Jaffer to appear on Thursday morning and threatened to start a contempt of Parliament process against him if he refuses.

Jaffer wrote that he "meant no disrespect" to MPs with his absence and said he wants to answer "all reasonable questions properly within the scope of the committee's mandate."

"I do not wish to extend this process, which has been tortuous for me and my family, any longer than necessary," he wrote.

Guergis resigned from Prime Minister Stephen Harper's cabinet, and was kicked out of the Conservative caucus in April after Harper learned of allegations about her conduct, which have yet to be disclosed. The prime minister also referred the matter to the RCMP and the federal ethics commissioner.

She continues to represent the central Ontario riding of Simcoe-Grey and has denied any wrongdoing.