This research shows that when an individual has a baby can be directly linked to the fertility decisions not only of their closest family and colleagues but of wider networks. The findings demonstrate for the first time and in a robust way, a clear fertility spillover effect from family to the workplace and vice versa.
The study uses register data from Statistics Netherlands on a group of people born in the 1970s and links them to create samples of more than 600,000 work colleagues and more than 70,000 sibling pairs.
A strong effect on the timing of becoming a parent ran between colleagues’ siblings and the individual concerned and siblings’ colleagues and the individual concerned. These effects occurred over a 3-year period following the transition to parenthood and were strongest 2-3 years after the initial birth and where the social interactions were between women.
The researchers conclude that without the ‘colleague effect’, there would have been 1,151 (5.8%) fewer pregnancies from a total of nearly 20,000 pregnancies identified in the study’s time period. For siblings, it was 315 (1.5%) from a total of just over 20,000.
The increasing availability of register data in various countries such as Denmark, Finland, Norway, and Sweden will make it possible to look at what’s going on in other countries and also to see if the spillover effect extends to other networks, such as neighbours.