Study explores impact of pandemics on birth rates in Switzerland

Researchers at UZH have studied the impact of pandemics on the birth rate in Switzerland for the first time. While the number of births unexpectedly rose initially during COVID-19, it fell significantly during previous pandemics in history.

Birth rates are currently declining in Switzerland, just like they are in other European countries. It is well established that the number of births is subject to medium-term fluctuations and also responds to pandemics or crises in the short term. However, there is less detailed research on the most recent trends - especially in relation to the COVID-19 pandemic.

Researchers from the University of Zurich have now examined the monthly birth figures in Switzerland between 1871 and 2022 and placed them in their relevant historical context. They did this using the data that is collected on a regular basis by the Swiss Federal Statistical Office (FSO) and the statistics chronicling the natural population change (BEVNAT) from 1987 to 2022. The team compared the monthly recorded statistics with the figures that would have been expected based on the previous year. Besides the long-term trends, the researchers were also particularly interested in earlier and more recent pandemic periods.

Thirteen percent more births during the pandemic

The study shows that the birth rate in Switzerland has generally been declining since around 2018 and is approaching a historical low. But in 2021, which was the second year of the COVID-19 pandemic, there was an unexpected temporary double-digit increase in the number of births of around 13 percent. More babies were conceived in particular in the first year of the pandemic in 2020, during and shortly after the implementation of the lockdown measures. "Our analysis shows that during this period the increase in births was particularly pronounced among Swiss women and mothers over the age of 30," says lead author Katarina Matthes from the Institute of Evolutionary Medicine.

The authors state that the precise reasons for this brief baby boom have not yet been established. But there are strong indications that the time spent at home and a better work/life balance during the pandemic made people bring forward their plans to get pregnant. In an international comparison, only France displayed a similar trend - Germany, Austria and Italy, by contrast, did not see such a significant increase in the birth rate as Switzerland.

Decline in births from February 2022

But following this temporary rise, from February 2022 Switzerland saw a renewed return to the previous negative trend in the birth rate. This applied in particular to non-Swiss women and mothers under the age of 30. The researchers suspect that in the spring of 2021 young women were being cautious and decided they would rather wait to receive their COVID-19 vaccination before getting pregnant.

In addition, there could be other reasons for the persistent decline in the number of births: "We might be seeing shifting values within society, with young people wanting fewer or even no children at all," explains Matthes. People perceive their own future to be insecure as a result of economic worries, uncertainty or climate change, and this could help explain the increase in the number of people choosing not to have children. As part of a UZH PRC grant, lead author Kaspar Staub will pursue this question further in an interdisciplinary project together with researchers from the UZH.

Drop in birth rate during previous pandemics

From a long-term perspective, the team of researchers were surprised to find the fluctuations in the birth rate during and after the COVID-19 pandemic, especially compared to other pandemics in the past.

We were able to highlight the fact that the pattern in the birth rate during and after the pandemics from 1889-90, 1918-20 and in 1957, in which a large proportion of the Swiss population fell ill, was different to the one seen during and after the COVID-19 pandemic."

Kaspar Staub, adjunct professor at the Institute of Evolutionary Medicine

For example, in the earlier pandemics, there was a drop in the birth rate of around 12 to 25% roughly six to nine months after the peak, but this did not last very long. The likely reasons for this are reduced fertility because of an infection and an increased rate of miscarriage. The authors surmise that the fact that the number of births did not decline in this way during the first phase of the COVID-19 pandemic is probably because the number of infections in the population at large was relatively low in 2020 thanks to the public-health measures that were taken to protect people.