Parental socioeconomic composition of birth cohorts changed during the COVID-19 pandemic.

The COVID-19 pandemic offers opportunities to study effects of in-utero and early life exposure to environmental changes. However, inferences from such studies may be flawed if the pandemic has changed the socioeconomic composition of parents. Analysing over 77.9 million live births from 15 countries, we estimate changes in the socioeconomic composition of the cohort born between December 2020 and December 2021 using interrupted time series analysis. We find that, compared with their counterfactual compositions, the December 2020-December 2021 birth cohort has a higher proportion of babies born to socioeconomically advantaged parents in Austria, England, Finland, the Netherlands, Scotland, Spain, Wales, and the United States while we observe the opposite change for Brazil, Colombia, Ecuador, and Mexico. These changes in cohort composition may cause between-cohort differences in life course outcomes that are influenced by parental socioeconomic circumstances even if early life exposure to the pandemic had no direct effect on this birth cohort.