Quantifying the postponement in the age at first attempt to conceive and its consequences
The substantial rise in the age at first birth in recent decades suggests that people are delaying their first attempt to have a child. The age at first birth, however, may not accurately reflect when people first attempt to conceive, given age-related declines in the ability to get pregnant and to achieve a live birth. Through a microsimulation model incorporating biological parameters and sequential Approximate Bayesian Computation, we estimate the distribution of the age at first attempt to conceive from 1960 to 1980 based on the age at first birth derived from Dutch administrative data. Over this period, the average age at first conception attempt, as inferred by the models, increases by two years. Unexpectedly, the average duration to childbirth remains stable despite later conception attempts, which is partly explained by a selection effect at advanced ages favouring couples with higher fecundity, with less fecund couples having higher rates of childlessness. We assess the influence of model assumptions on our results and underscore the promise of Approximate Bayesian Computation for future demographic and fertility research.
Quantifying the postponement in the age at first attempt to conceive and its consequences
Vienna Yearbook of Population Research
Gert Stulp, Rolf Granholm, Amke M. G. van Tintelen, Zoltán Lippényi
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The substantial rise in the age at first birth in recent decades suggests that people are delaying their first attempt to have a child. The age at first birth, however, may not accurately reflect when people first attempt to conceive, given age-related declines in the ability to get pregnant and to achieve a live birth. Through a microsimulation model incorporating biological parameters and sequential Approximate Bayesian Computation, we estimate the distribution of the age at first attempt to conceive from 1960 to 1980 based on the age at first birth derived from Dutch administrative data. Over this period, the average age at first conception attempt, as inferred by the models, increases by two years. Unexpectedly, the average duration to childbirth remains stable despite later conception attempts, which is partly explained by a selection effect at advanced ages favouring couples with higher fecundity, with less fecund couples having higher rates of childlessness. We assess the influence of model assumptions on our results and underscore the promise of Approximate Bayesian Computation for future demographic and fertility research.