Prenatal maternal stress has been linked to multiple adverse outcomes. Researchers have used a variety of methods to assess maternal stress. The purpose of this study was to explore and compare factors associated with stress in pregnancy as measured by perceived stress and stressful life events. We analyzed data from the Canadian Maternity Experiences Survey. A randomly selected sample of 8,542 women who had recently given birth was drawn from the 2006 Canadian Census. Women were eligible if they were at least 15 years of age, had delivered a live, singleton infant, and were living with their infant at the time of the interview (5-14 months postpartum). Prevalence estimates and odds ratios were calculated using sample weights of the survey and their variances were calculated using bootstrapping methods. Bivariate analyses identified statistically significant factors associated with each stress measure. Backward stepwise multivariate logistic regression models were constructed. A total of 6,421 women (78%) participated in the computer assisted telephone interview. Twelve percent of women experienced high levels of perceived stress and 17.1% reported having three or more stressful life events in the year prior to the birth of their baby. In the final model, psychosocial variables were associated with both outcomes, whereas demographic factors were associated only with life event stress. Different factors contributed to perceived stress and life event stress, suggesting that these concepts measure different aspects of stress. These findings can inform routine psychosocial risk assessment in pregnancy.