Mental disorders and having a first child among young adults: a nationwide register-based cohort study

Objective: To examine associations between mental disorders and time to the first childbirth among young people in Finland, and to investigate whether partnership status mediates these associations.Design: A nationwide register-based cohort study.Setting: Primary and secondary healthcare data from Finland.Population or Sample: All individuals born in 1980–1995 who were childless and living in Finland at age 16 (n=1,210,662). Methods: Cox proportional hazards models were used to examine associations between mental disorders and time to the first childbirth. The participants were followed until the birth of a first child, death, emigration, or the end of 2019.Main Outcome Measures: Time to a first live childbirth.Results: Both men and women diagnosed with mental disorders prior to parenthood had a lower likelihood of having their first child compared to those without such diagnoses during the follow-up. People diagnosed with schizophrenia and intellectual disabilities were the least likely to become parents. After controlling for partnership status, these associations attenuated for all mental disorders. Before age 25, substance use, childhood onset, anxiety, or any mental disorders were associated with a higher likelihood of having a first child, but this changed with age, so that after age 30 mental disorders were associated with a lower likelihood of parenthood. Conclusions: Almost all mental disorders were associated with a lower likelihood of having a first child among young people born in 1980–1995. These findings imply that well-functioning mental health services are important from a fertility perspective, which should be considered by policy makers.