Fertility dynamics through historical pandemics and COVID-19 in Switzerland, 1871-2022.

We follow general fertility rates (GFRs) in Switzerland up to 2022, with a focus on their dynamics during and after pandemics. Historical influenza pandemics (1889-90, 1918-20, 1957) have consistently led to temporary declines in births between six and nine months after the pandemic peak. High rates of miscarriage may explain these findings. After the 1889-90 and 1918-20 pandemics, short-term baby booms occurred. For the recent Covid-19 pandemic, the dynamics appear more complex. The GFR had already been declining since 2018, before the pandemic hit Switzerland. During and shortly after the first two waves in 2020, there was an increase in conceptions, leading to a higher GFR in 2021: shutdown measures may have brought planned pregnancies forwards. Subsequently, the GFR declined from February 2022; one possible explanation is that pregnancies were intentionally postponed until after vaccination. Following these population-level observations, more in-depth studies are needed to understand better why fertility is affected by pandemics.