Anti-Phospholipid Antibodies in Women with Placenta-Mediated Complications Delivered at >34 Weeks of Gestation.

OBJECTIVE:To determine the prevalence of positive antiphospholipid (aPL) antibodies among pregnant women with placenta-mediated complications delivered at >340/7 weeks of gestation.METHODS:This was a single-center retrospective observational study conducted between 2017 and 2022. Inclusion criteria included pregnant or post-partum women, >18 years, diagnosed with any of the following placenta-mediated complications and delivered at >340/7 weeks of gestation: small-for-gestational-age neonate (SGA ≤ 5th percentile according to local birthweight charts), preeclampsia with severe features, and placental abruption. The primary outcome was the prevalence of positive aPL antibodies: Lupus anticoagulant, Anticardiolipin, or Anti-ß2glycoprotein1.RESULTS:Overall, 431 women met the inclusion criteria. Of them, 378(87.7%) had an SGA neonate, 30 had preeclampsia with severe features (7%), 23 had placental abruption (5.3%), and 21 patients had multiple diagnoses(4.9%). The prevalence of aPL antibodies in the cohort was 4.9% and was comparable between the three subgroups (SGA-3.9%; PET with severe features-3.3%; and placental abruption-13% (p = 0.17)).CONCLUSION:aPL antibodies prevalence in women with placenta-mediated complications > 34 weeks of gestation was 4.9%, with comparable prevalence rates among the three subgroups. Future prospective studies are needed to delineate the need for treatment in those who tested positive for aPL antibodies and do not meet Anti-Phospholipid Antibody Syndrome clinical criteria.