Fertility and Well-Being
At a Glance
Costs and Gains of Postponing Parenthood
Conducted by Mikko Myrskylä; Kieron Barclay, Pekka Martikainen (MPIDR / University of Helsinki, Finland); in Collaboration with Martin Kolk (Stockholm University, Sweden), Irma T. Elo (University of Pennsylvania, Philadelphia, USA), Ruben C. Arslan (Georg-August-Universität Göttingen, Germany), Alice Goisis (University College London, United Kingdom), Kai Willführ (Carl von Ossietzky University of Oldenburg, Germany), Berkay Özcan (London School of Economics and Political Science, United Kingdom)
Maternal and paternal ages at birth are increasing across the developed world, giving rise to concerns about the individual- and population-level effects of fertility postponement on the health of parents and offspring. We analyze how parental age at the time of childbearing is associated with individual-level outcomes for both parents and their children, which mechanisms might be responsible for these associations, and whether these relationships are causal. We seek to distinguish the separate contributions of parental biological aging, resource accumulation, and changing period conditions to the association between parental age and child outcomes.
Projects in this research area focus on a wide range of outcomes for the offspring of older parents, including their cognitive ability, health, education, career success, and mortality. We also examine whether the age at childbearing and the number of children affect the mortality of the parents themselves. We use methods that compare siblings to account for unobserved parental characteristics. To cover a wide range of contexts in which the relative importance of aging, resources, and period conditions might differ, we use large population-based samples from the US register-based data from Scandinavian countries, Demographic and Health Surveys, and other sources.
Thus far, this project has generated several arresting new insights. For example, using Finnish population data and a sibling fixed-effects approach in order to minimize residual confounding from unmeasured factors, Goisis et al. (2017) found that the previously widely documented associations between maternal age at the time of birth and the risks of preterm birth and low birth weight are highly exaggerated.
Regarding the changing composition of older mothers over time, Goisis et al. found marked changes in the association between advanced maternal age and the risk of low birth weight, as well as child cognitive development. In the UK of the 1950s, children born to mothers aged 35 or older had a substantially elevated risk of having a low birth weight; those born to older mothers had lower cognitive ability levels than children born to mothers in their prime childbearing ages. In the 2000s, however, these associations weakened considerably or they even reversed: Children born to older parents had no elevated risk of low birth weight, and they had above-average cognitive ability levels. This is because children born to older mothers in the 1950s were high-parity children; whereas in the 2000s, the children of older mothers were born into small families of higher socioeconomic status, which gave them some distinct advantages.
This project was partially funded by the European Research Council Starting Grant for the years 2014–2019 (grant number; “Costs and Gains to Postponement: How Changes in the Age of Parenthood Influence the Health and Well-being of Children, the Parents, and Populations (COSTPOST)” PI: Mikko Myrskylä). This project was conducted in collaboration with the London School of Economics and Political Science.
Fertility Development, Health Care, Public Health, Medicine, and Epidemiology
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