Background: Although demographers have long been interested in studying the historical fertility transition, there is still a lack of knowledge about disaggregated patterns. Identifying these patterns could help us to better understand the mechanisms behind the transition.

Objective: The aim of this paper is to explore social class differentials in fertility before, during, and after the fertility decline, in order to test hypotheses regarding a reversal of class differences during the transition.

Methods: We use micro-level census data for Sweden 1880, 1890, 1900, 1960, and 1970 with individual-level information on occupation, which is used to measure class. Poisson regressions with parish-level fixed effects enable us to carefully control spatial heterogeneity in measuring class differences in net fertility (child-woman ratios).

Results: The relative differences were about as large in the early phases of the transition as they were in the 1960s. The fertility levels of the high-fertility classes were about 40% higher than those of the low-fertility classes. In the early phases of the decline, the upper and middle classes had much lower net fertility than lower skilled workers, who had the highest fertility levels. However, there was no clear gradient from the highest to the lowest socioeconomic status. Instead, it appears that the upper and middle classes had low fertility levels, while the fertility levels of the remaining groups were unchanged, and therefore remained relatively high. In the 1960s, members of the middle class had the lowest fertility levels, while farmers and rural laborers had the highest fertility levels.

Conclusions: The results only partly confirm the assumption that there was a reversal in class differences in the demographic transition. Class was found to be important, but the pattern was not characterized by a simple gradient. Moreover, spatial heterogeneity was shown to explain about half of the observed differences between classes. The observed pattern suggests that the fertility transition can be attributed to both innovation-diffusion and the adjustment to new socioeconomic conditions.