Background: Historically, the French Canadian population of Quebec, Canada, is known for its high fertility, which lasted well into the 20th century, and for its late fertility transition. Within Quebec, regions such as Saguenay are known for having experienced an even more delayed fertility transition.

Objective: In Quebec, as elsewhere, various factors modulated the transition, and differential behaviors and timing can be observed across socioeconomic groups. These factors are studied here in the context of the Saguenay region, where particularly rich data are available. The region was mostly rural at first, but industrialization and urbanization occurring since the beginning of the 20th century allow us to study socioeconomic reproductive differentials before and during the transition.

Methods: To do so, we rely on the BALSAC database, which contains all church and civil records from the onset of colonization around 1840 up to 1971. In addition to the usual descriptive statistics, we use Cox models to analyze the probability of having a first birth and higher order births among four socioeconomic groups defined with HISCLASS coding.

Results: The results demonstrate the late timing of the transition and a clear progression from the non-manual and skilled workers, who show the first signs of declining fertility during the 1930s, to the farmers, who do the same only at the end of the 1950s. As a result, socioeconomic fertility differentials widened during the transition period.

Conclusions: Even in a context where the transition was significantly delayed compared to most other regions studied in this issue, some socioeconomic differentials were observed prior to the transition, and they widened during the transition due to the differential progression of contraceptive practices among couples.