SARS-CoV-2 infection in singleton pregnant women increases antiphospholipid antibody prevalence and placental dysfunction risk.

To investigate the prevalence of antiphospholipid antibodies (aPLs) in pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and their impact on maternal-fetal outcomes, with an emphasis on gestational stage-specific differences and lupus anticoagulant (LAC) positivity. This prospective, observational cohort study was conducted at the Department of Obstetrics, Peking University People’s Hospital, from December 2022 to January 2023. Eligible participants were singleton pregnant women without pre-existing pregnancy complications who tested positive for SARS-CoV-2. Serum samples were collected 2–4 weeks post-infection for testing of aPLs, including LAC, anti-β2-glycoprotein I (aβ2GPI), and anticardiolipin antibodies. Maternal and fetal outcomes were monitored according to standard prenatal care protocols, with specific attention to placental dysfunction related complications. The overall prevalence of aPLs in pregnant women infected with SARS-CoV-2 was 18.75%. All positive cases were single-antibody positive, either for aβ2GPI or LAC, with no instances of multiple antibody co-positivity. The prevalence of aPLs was significantly correlated with the gestational stage at the time of infection, rising from 5.88% in the first trimester to 16.00% in the second trimester and 26.31% in the third trimester (P SARS-CoV-2 infection during pregnancy significantly increases the prevalence of aPLs, with a pattern that is dependent on the gestational stage. Positivity for aPLs, particularly LAC, is an independent risk factor for complications related to placental dysfunction. Our findings suggest that pregnant women infected with SARS-CoV-2, especially those in the third trimester, should undergo aPLs screening 2–4 weeks post-infection, along with enhanced monitoring for placental dysfunction, there should be vigilant surveillance of infection status, coagulation function, and appropriate obstetric management.