The province says the report by child and adolescent psychiatrist Jana Davidson is expected to be finished late next month, about a month later than it was initially due to be completed.
Davidson, an expert from British Columbia, was appointed after an earlier report into the case raised concerns about the hospital.
She has also been asked to examine procedures within the Capital District Health Authority and make recommendations to address gaps in treatment and counselling services for young people who are suicidal.
Another report commissioned by the province into the Halifax school board's handling of the case called for an independent review of the IWK.
The report said Parsons was admitted to the hospital in March 2012, about five months after the 17-year-old girl was allegedly sexually assaulted and became suicidal.
Her family alleges she was sexually assaulted by four boys and a digital photograph of the incident was passed around her school.
She died in April after she was taken off life-support following an attempted suicide.
Glenn Canning, Rehtaeh's father, has said he would like Davidson's study to directly address his daughter's care in the hospital, which lasted about five weeks, because he doesn't believe she received the help she needed.
Davidson, who is the psychiatrist-in-chief of children's programs at the Children's and Women's Health Centre of British Columbia, has said she will not read the specifics of what happened in the case or interview people who treated her.
At the time of her apppointment this summer, Davidson said her focus will be more generally on treatment and counselling services for young people and their families when there is a risk of suicide.
Kevin McNamara, deputy minister of Health and Wellness, has said there are legal restrictions preventing reviewers from looking at specific patient cases — even if a single case provokes the review.
The review was estimated to cost about $15,000.