The Lockdown Cohort-Effect: Does the unequal impact of the COVID-19 pandemic on fertility lead to long-term consequences for health and public services provision?

The COVID-19 pandemic placed a heavy social and health burden on populations. Yet, because of social inequalities in the pandemic's impact on fertility behaviour, babies conceived during the pandemic may be the most socially advantaged and healthiest birth cohort of the last decades. Research on this counterintuitive but realistic consequence of the pandemic - the Lockdown Cohort (LoCo)-Effect - is critical for public policy and the understanding of pandemic consequences. As individual-level register data for babies conceived and born in 2021 and later is only just becoming available, we still know little about how the pandemic changed the composition of parents and to what extent this explains changes in birth outcomes for those born during the pandemic. To address this knowledge gap, I will use individual-level register data (2010-2022) from Finland, Scotland, Austria, Spain, the United States, and Brazil and natural experimental methods to study the LoCo-effect comparatively. This strengthens the generalisability of results across different welfare regimes and pandemic experiences. First, I will study the magnitude of compositional changes in parental characteristics due to the unequal impact of the pandemic on fertility. Second, I will analyse the extent to which differences in prematurity and birth weight between the LoCo and earlier cohorts are caused by this change in parental characteristics. Third, I will estimate how the pandemic has affected intersectional social inequalities in birthweight and preterm birth. This project is innovative because it bridges disconnected debates in demography, epidemiology, and sociology to explain why, against expectations, pregnancy and birth outcomes have improved during the pandemic. As parental characteristics and birth outcomes shape health, developmental, and socioeconomic outcomes throughout life, the results of this project will influence social and public health research and policy for decades to come.