Federal Institute for population research, Germany:

Fertility declines near the end of the COVID-19 pandemic: Evidence of the 2022 birth declines in Germany and Sweden

"Following the onset of the COVID-19 pandemic, several countries faced short-term fertility declines in 2020 and 2021, a development which did not materialize in Scandinavian and German-speaking countries. However, more recent birth statistics show a steep fertility decline in the aftermath of the pandemic in 2022.

The seasonally adjusted monthly TFR of Germany dropped from 1.5-1.6 in 2021 to 1.3-1.4 in 2022, a decline of about 14 %. In Sweden, the corresponding TFR dropped from about 1.7 in 2021 to 1.5-1.6 in 2022, a decline of almost 10 %. There is no association of the fertility trends with changes in unemployment, infection rates, or COVID-19 deaths.

The association between the onset of mass vaccinations and subsequent fertility decline indicates that people adjusted their behaviour to get vaccinated before becoming pregnant, as societies were opening up with post-pandemic life conditions."

Love the conjecture in their conclusions.