2026-02-05 リンショーピング大学
<関連情報>
- https://liu.se/en/news-item/no-link-between-the-covid-vaccine-and-reduced-childbirth
- https://www.nature.com/articles/s43856-026-01396-x
スウェーデンでは、COVID-19ワクチン接種と出産率に関連性はない COVID-19 vaccination carries no association with childbirth rates in Sweden
Dennis Nordvall,Thomas Schön,Jorma Hinkula,Olle Eriksson,Armin Spreco,Örjan Dahlström,Johan Lyth,Daniel Axelsson,Elin Gursky,Marie Blomberg & Toomas Timpka
Communications Medicine Published:21 January 2026
DOI:https://doi.org/10.1038/s43856-026-01396-x An unedited version of this manuscript
Abstract
Background
Speculative claims about COVID-19 vaccines affecting fertility and childbirth have circulated widely. We aimed to examine whether COVID-19 vaccination is causally associated with childbirth in Swedish women.
Methods
We conducted a cohort study using a representative population of 369,000 to emulate a randomized experiment, comparing childbirth rates between vaccinated and unvaccinated women. Cox proportional hazards models were applied, treating vaccination as a time-varying covariate. Causal modeling was used to adjust for potential bias. To capture vaccine effects on both conception and established pregnancies, the index event was set at an estimated conception date, 280 days prior to childbirth.
Results
We show that with an assumed average pregnancy length of 280 days, there are no statistically significant associations between COVID-19 vaccination and childbirth (unadjusted HR = 0.94 (95% CI 0.89-1.00); adjusted HR = 1.03 (95% CI 0.97-1.09). Assuming a shorter pregnancy length (266 days), the associations between vaccination and childbirth remain insignificant (unadjusted HR = 0.96 (95% CI 0.90-1.02); adjusted HR = 1.04 (95% CI 0.98-1.11)). Neither are there statistically significant associations between COVID-19 vaccination and recorded miscarriages (unadjusted HR = 0.84 (95% CI 0.69-1.03); adjusted HR = 0.86 (95% CI 0.70-1.05).
Conclusions
COVID-19 vaccination is not associated with a decrease in childbirth after adjusting for common confounding factors. These findings provide evidence to support vaccination policies for women of childbearing age.
Plain Language Summary
Early, unfounded rumors spread during the COVID-19 pandemic claimed that mRNA vaccination could cause infertility. Later, suspicions were raised regarding whether reductions in childbirth observed during the pandemic were associated with the novel COVID-19 vaccines. We therefore study effects of COVID-19 vaccination in a representative population of Swedish women, and adjust for any confounding effects. No association is observed between COVID-19 vaccination and childbirth, or between vaccination and recorded miscarriages. We thus find no evidence for any connections between COVID-19 vaccination and the observed decrease in childbirth. Our results are relevant for consideration when vaccination policies involving women of childbearing age are determined.
