CALGARY -- The lawyer for a Calgary woman found guilty in the death of her son from a strep infection says the conviction should be overturned due to unreasonable delay.

Tamara Lovett treated her seven-year-old boy with holistic medicines before he died.

Alain Hepner says Lovett was charged in November 2013, but her trial didn't go ahead until 36 months later.

Hepner says his client's constitutional right to a timely trial was violated, so he is making his argument under a Supreme Court of Canada decision from last year.

The high court ruled a criminal trial that takes longer than 30 months to begin violates an accused's charter rights.

Hepner says he rejects the Crown's position that the defence should be held responsible for a six-month delay in Lovett's case because he was unavailable for an earlier trial.

Lovett was found guilty in January of criminal negligence causing death. The judge said she "gambled away" the life of her son Ryan by treating him with herbal remedies without seeking medical help.