Statistics Canada said 90 per cent of children between the ages of one and three living outside Quebec had working mothers who temporarily left their jobs after giving birth.
Their average leave was 44 weeks, the agency said.
About 26 per cent of these children had working fathers who also stayed home after they were born. Fathers took an average of 2.4 weeks off work.
Statistics Canada said most mothers — 83 per cent — took paid leave. Around one in five mothers took unpaid leave. The average length of paid leave was 40 weeks, while the average for unpaid leave was 4.5 weeks.
"A number of factors, including socio-economic and child and maternal health characteristics, were associated with whether mothers and fathers took leave and with the length of leave," the agency said.
The report covered the 2010-11 period.
In Quebec, which has its own parental benefits program, almost all mothers took some form of leave.
Ninety-nine per cent of children living in Quebec had working mothers, who stayed home an average of 48 weeks after childbirth.
The Quebec Parental Insurance Plan differs from the Canada Employment Insurance Program available in other provinces and territories.
More mothers in Quebec took paid leave than in other provinces. About 97 per cent of children had mothers who took paid leave, while 21 per cent reported unpaid leave.
About three-quarters of fathers in Quebec stayed home after the birth of their children.
In Quebec and the rest of Canada, the agency said self-employment determined the length of time off work.
"Both mothers and fathers who were self-employed took shorter leaves, even after considering factors such as whether the child was first-born, the sex of the child, the mother's age, and parental education and income," the study read.
Statistics Canada said mothers who reported postpartum depression had higher odds of taking leave. They took more time off work than mothers who did not report postpartum depression.