Preconception Non-criteria Antiphospholipid Antibodies and Risk of Subsequent Early Pregnancy Loss: a Retrospective Study

The aim of this study was to investigate the subsequent early pregnancy outcomes in women positive for non-criteria antiphospholipid antibodies (NC-aPLs) before pregnancy. A total of 273 patients who had experienced sporadic or recurrent pregnancy loss and had been screened for 13 NC-aPLs at preconception were recruited in this study from September 2019 to February 2022. Serum levels of NC-aPLs were measured by ELISA using specific kits. The primary outcome was early pregnancy loss, and the secondary outcomes were biochemical pregnancy, clinically confirmed pregnancy loss, and ongoing pregnancy. Among these subjects, 56 patients had one previous pregnancy loss, and 217 had recurrent pregnancy loss (RPL). The NC-aPLs (+) and NC-aPLs (-) groups had similar rates of early pregnancy loss (EPL) after adjustment, regardless of the number of positive NC-aPLs (aOR = 1.054, 95% CI 0.602-1.846). Other outcomes were comparable in both groups, including the rates of biochemical pregnancy (aOR = 1.344, 95% CI 0.427-4.236), clinically confirmed pregnancy loss (aOR = 0.744, 95% CI 0.236-2.344), and ongoing pregnancy (aOR = 0.949, 95% CI 0.542-1.660). Based on sensitivity analysis, the NC-aPLs (+) were not associated with adverse early pregnancy outcomes in women with RPL. Furthermore, the difference in gestational weeks of pregnancy loss between the two groups was also insignificant. This study found no evidence linking preconception NC-aPL positivity to early pregnancy outcomes but offers a reference for future research to clarify NC-aPLs' potential clinical impact.