In the course of the nineteenth century, millions of migrants moved to and settled permanently in western European urban centres. This large influx of immigrants, originating from various regions with different demographic backgrounds, affected the level and pace of the local fertility transition. In this study we sampled and analyzed 747 couples consisting of natives and immigrants in the city of Antwerp during the early fertility transition. Stopping behaviour of both native, immigrant and mixed couples is analyzed. We found that adult migrants display stopping behaviour that resembles that at their origin while individuals that immigrated during childhood adapt more often to the dominant local fertility pattern. While the migratory status of the mother was more decisive than that of the father, couples consisting of both immigrants were the last to implement more efficient reproductive strategies. By focusing on individual behavioural patterns, new light is shed on the diffusion of reproductive behaviour during the Western European fertility decline.