Association of inactivated COVID‐19 vaccination with maternal coagulation function in early pregnancy.

Reports of rare but severe thrombotic events after receiving some COVID‐19 vaccines brought concerns for the possibility of vaccine‐induced coagulation abnormality. However, no study has reported the impacts of COVID‐19 vaccination on coagulation function in pregnant women. We aimed to explore whether vaccination with inactivated COVID‐19 vaccines before pregnancy was associated with coagulation changes in pregnant women. We conducted a retrospective cohort study in a tertiary‐care hospital in Shanghai, China. A total of 5166 pregnant women were included, of whom 2721 (52.7%) completed vaccination before conception. Compared with unvaccinated women, the mean serum levels of prothrombin time (PT) and fibrinogen (FIB) were lower in vaccinated women by 0.09 (β = −0.09, 95% confidence interval [CI], −0.13, −0.05) mg/L and 0.11 (β = −0.11, 95% CI, −0.15, −0.07) mg/L, and the mean D‐Dimer (D‐D) levels were higher by 0.12 (β = 0.12, 95% CI, 0.09, 0.15) mg/L. However, no significant association was observed between COVID‐19 vaccination and serum levels of activated partial thromboplastin time (APTT), fibrinogen degradation product (FDP) or thrombin time (TT). Our findings suggested that inactivated COVID‐19 vaccination before conception resulted in a small change in maternal coagulation function, but this might not have clinical significance. [ABSTRACT FROM AUTHOR]