A large population-based study in Sweden has found no association between COVID-19 vaccination and reduced childbirth rates, providing further evidence against persistent claims linking the vaccines to fertility problems. The findings were published in Communications Medicine.
Researchers analysed data from 59,773 females aged 18 to 45 years in the Swedish county of Jönköping, using regional healthcare records covering 2016 to 2024. COVID-19 vaccination became available to adults in Sweden from January 2021, with most participants (75.5%) receiving basic vaccination, predominantly mRNA vaccines.
Using Cox proportional hazards models with vaccination treated as a time-varying exposure, researchers found no significant association between COVID-19 vaccination and childbirth rates. Adjusted hazard ratios were close to one across primary and sensitivity analyses. A separate analysis also found no significant link between vaccination and miscarriage rates.
The study addressed widespread misinformation on social media suggesting that mRNA vaccines could cause infertility or contribute to declining birth rates observed during the pandemic. The researchers noted that childbirth rates in Sweden declined by 8% between 2021 and 2022, with smaller decreases in subsequent years. However, they attributed these trends to behavioural changes during lockdowns, pandemic-related socioeconomic conditions, and broader shifts in fertility intentions rather than vaccination.
The authors also highlighted demographic factors, noting that the pool of prospective parents was already smaller due to lower birth rates in earlier decades. They acknowledged limitations, including potential selection bias from relying on childbirth records, which may not capture early pregnancy losses.
The findings add to existing epidemiological evidence showing no negative associations between COVID-19 vaccination during pregnancy and outcomes such as preterm birth or foetal development.
Source: News Medical / Communications Medicine (2026)
