Patients with obstetric antiphospholipid syndrome (OAPS) and noncriteria OAPS (NC-OAPS) may demonstrate significant clinical and laboratory differences, according to study results reported in Rheumatology.

OAPS is the most common treatable autoimmune disease in women with pregnancy. In this study, researchers used historical and current data from the multicenter European Registry on Obstetric Antiphospholipid Syndrome to compare clinical features, laboratory data, and fetal-maternal outcomes between 1000 female patients with OAPS and 640 patients with NC-OAPS, or antiphospholipid antibody-related obstetric complications that did not fulfill Sydney criteria. Patients were classified as category I (double or triple positivity for antiphospholipid antibodies) or category II (only 1 positivity for antiphospholipid antibodies).

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Significant differences were observed between the patient groups in both categorization and prevalence of obstetric complications. More patients were classified as category I in the OAPS group compared with the NC-OAPS group (29.2% vs 17.9%; P <.0001); conversely, more women were classified as category II in the NC-OAPS group compared with the OAPS group (82% vs 70.8%; P <.0001).

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Complications occurred in 65.1% of patients with OAPS and in 73.4% of patients with NC-OAPS (P <.001). In patients with OAPS, the most frequent complication was prematurity (24.1%), whereas in patients with NC-OAPS, miscarriage was the most frequent complication (19.4%). No differences were observed in rates of live births and thrombotic complications.

Treatment with preconceptional low-dose aspirin and prophylactic low-molecular-weight heparin was administered to 44.8% of patients with OAPS and 48.12% of patients with NC-OAPS. Of these patients, 85% of those with OAPS and 89.6% of those with NC-OAPS experienced good obstetric outcomes including live births.

The authors concluded that “NC-OAPS should be considered a treatable cause of poor antiphospholipid antibody-related obstetric outcomes” and that “the benefits of treating these [patients] during pregnancy outweigh those of not treating them.”


1.     Alijotas-Reig J, Esteve-Valverde E, Ferrer-Oliveras R, et al. Comparative study of obstetric antiphospholipid syndrome (OAPS) and non-criteria obstetric APS (NC-OAPS): report of 1640 cases from the EUROAPS registry [published October 3, 2019]. Rheumatology. doi:10.1093/rheumatology/kez419