Salmon migration and fertility in East Germany: an analysis of birth dynamics around German reunification

Kreyenfeld, M. R., Vatterrott, A.
Zeitschrift für Familienforschung/Journal of Family Research, 30:3, 247–268 (2018)


This paper uses rich administrative data from the German Pension Fund to describe changes in the timing and the spacing of births that occurred in the period following German reunification. We examine differences in the birth dynamics of East Germans, West Germans, and women who migrated between the two parts of Germany in these years. As the pension registers provide monthly records on whether a person is living in East or West Germany, they also allow us to examine the role of regional mobility in birth behaviour. In particular, we test the “salmon hypothesis”, which suggests that migrants are likely to postpone having a child until after or around the time they return to their region of origin. Our investigation shows that a large fraction of the cohorts born in 1965-74 migrated to West Germany after reunification, but that around 50% of these migrants returned to East Germany before reaching age 40. The first birth risks of those who returned were elevated, which suggests that the salmon hypothesis explains the behaviour of a significant fraction of the East German population who moved in the period following German reunification.

Schlagwörter: Deutschland, Deutschland, Alte Bundesländer, Deutschland, Neue Bundesländer, fertility, internal migration, return migration
Das Max-Planck-Institut für demografische Forschung (MPIDR) in Rostock ist eines der international führenden Zentren für Bevölkerungswissenschaft. Es gehört zur Max-Planck-Gesellschaft, einer der weltweit renommiertesten Forschungsgemeinschaften.