Project Publications

Change in the perceived reproductive age window and delayed fertility in Europe


Ester Lazzari, Marie-Caroline Compans, Eva Beaujouan

While extensive literature documents the massive fertility delay of recent decades, knowledge about whether and how attitudes towards the timing of births have changed in Europe remains limited. Using data from two rounds of the European Social Survey, we investigate these changes and their association with macro-level fertility indicators in 21 countries. Between 2006–07 and 2018–19, societal consensus regarding the existence of optimal childbearing ages remained strong and became more in favour of later parenthood. Decomposition analyses show that these shifts were driven only partially by changes in population composition, supporting the idea that a general attitudinal change in favour of later childbearing is underway. We also find a trend towards gender convergence in upper age limits driven by the increasing social recognition of an age deadline for men’s childbearing.

Impacts of COVID-19 on Medically Assisted Live Birth Rates in the United States in 2020 and 2021


Katherine Tierney, Ester Lazzari

Initial declines in births due to medically assisted reproduction (MAR) in December 2020 have been documented. However, the longer-term impact of COVID-19 on U.S. MAR birth rates has not yet been evaluated. Negative-binomial regression analyses were employed using counts of MAR births from the National Vital Statistics System and female population counts from the Current Population Survey as the exposure variable. Interaction terms were used to investigate whether trends varied by sociodemographic groups. Overall, however, the yearly incidence rates of MAR births in 2020 and 2021 were not different from rates from prior years (2017–2019). Thus, COVID-19 service suspension likely had a substantive effect on U.S. MAR birth rates, but this reduction quickly rebounded to pre-pandemic levels. This study extends prior research, which focused on data from 2020, and sheds further light on behavior related to MAR use and its potential demographic implications during the pandemic.

Explaining the urban–rural gradient in later fertility in Europe

Bernhard Riederer, Eva Beaujouan

Demographic research shows that, in Europe, fertility takes place later and is lower in cities than in rural areas. One might expect fertility to be delayed in urban areas because of longer periods in education and enhanced career opportunities. We examine how prevalent later fertility (35+ and 40+) is along the urban–rural axis, and whether differences can be explained by economic, cultural and compositional factors. We estimate multilevel random coefficient models, employing aggregated Eurostat data of 1328 Nomenclature des unités territoriales statistiques (NUTS) 3 and 270 NUTS 2 regions from 28 European countries. The urban–rural gradient in later fertility considerably diminishes once factors describing the economic environment, family and gender norms as well as population composition are accounted for. The higher prevalence of later fertility in cities is particularly associated with higher female education, greater wealth and a higher share of employment in high-technology sectors.

Femmes sans enfant : la part de l’infertilité

Eva Beaujouan, Ester Lazzari

Récemment, la part des femmes sans enfant dans la population a commencé à se stabiliser dans certains pays d’Europe, tandis qu’elle reste en plein essor dans d’autres. Dans cet article, nous faisons le point sur l’évolution de l’infécondité, ces dernières décennies, en Europe et en Asie de l’Est, c’est-à-dire sur l’évolution de la part des femmes qui n’ont pas eu d’enfant au cours de leur vie reproductive.

Delayed Fertility as a Driver of Fertility Decline?

Eva Beaujouan

A major transformation of life in the last decades has been the delay in fertility – that is, the decrease in fertility among people below age 25–30. At the same time that fertility has been delayed, the proportion of people having children later in life has increased, but in many countries, completed fertility has declined. This chapter (re)considers the extent to which these three phenomena –fertility delay, increase in later fertility, and fertility decline – are related and examines whether fertility delay causes fertility decline since an increasing number of people faces constraints to childbearing in later life. Finally, the relevance of changes in partnership dynamics for fertility decline is discussed on future completed fertility.

Projecting the Contribution of Assisted Reproductive Technology to Completed Cohort Fertility

Ester Lazzari, Michaela Potančoková, Tomáš Sobotka, Edith Gray & Georgina M. Chambers

Assisted reproductive technology (ART) is increasingly influencing the fertility trends of high-income countries characterized by a pattern of delayed childbearing. However, research on the impact of ART on completed fertility is limited and the extent to which delayed births are realized later in life through ART is not well understood. This study uses data from Australian fertility clinics and national birth registries to project the contribution of ART for cohorts of women that have not yet completed their reproductive life and estimate the role played by ART in the fertility ‘recuperation’ process. Assuming that the increasing trends in ART success rates and treatment rates continue, the projection shows that the contribution of ART-conceived births to completed fertility will increase from 2.1% among women born in 1968 to 5.7% among women born in 1986. ART is projected to substantially affect the extent to which childbearing delay will be compensated at older ages, suggesting that its availability may become an important factor in helping women to achieve their reproductive plans later in life.

Parental Sociodemographics of Medically Assisted Reproduction Births in the United States: A Dyadic Population-Level Study

Ester Lazzari, Katherine Tierney

The objective of the study is to find out how men’s and couples’ sociodemographic characteristics predict the probability of having a birth conceived using medically assisted reproduction (MAR) in the United States. To comprehend the environment in which MAR–conceived children are born and raised, performing dyadic analyses that examine the characteristics of both partners is essential. The findings underscore the enduring presence of substantial social disparities in MAR use in the United States, with MAR-conceived children raised in environments of relative advantage, which may impact their future health and development.