Risk factors for adverse pregnancy outcomes in obstetric antiphospholipid syndrome

Background: Antiphospholipid syndrome (APS) causes adverse obstetric outcomes in the affected patients. Our study aimed to investigate the risk factors for adverse pregnancy outcomes (APOs) in women with APS. Methods: This retrospective study included 143 pregnant women with APS admitted to Peking University People’s Hospital. Based on the presence of APOs, pregnant women were divided into the adverse outcomes group (n=49) and the non-adverse outcomes group (n=94). Clinical data were extracted from medical records. Univariate and multivariate logistic regression analyses were used to identify the risk factors associated with APOs. Results: We found that the low platelet count (≤50×10 9 /L), hypertension during pregnancy, and single-positivity of antiphospholipid antibody (aPLs) were the risk factors of APOs after adjusting age, the number of prior spontaneous miscarriages, weight change during pregnancy, gestational diabetes, thrombosis, oligohydramnios, and aPLs status (model I). Of importance, hypertension during pregnancy and single-positivity of aPLs remained the risk factors for adverse outcomes, but the low platelet count (≤50×10 9 /L) was no longer a risk factor after adding the adjustments of the time of diagnosis and treatment during pregnancy (model II). And the number of platelets increased after delivery under the treatment (87.53±49.81 vs. 65.06±41.3 vs. 52.75±20.70 vs. 110.19±55.30; p <0.05). Therefore, treatment could effectively decrease the risk of adverse outcomes in pregnant APS patients with thrombocytopenia. Conclusion: APS increases the risk of adverse outcomes during pregnancy. Thrombocytopenia, hypertension during pregnancy, and single-positivity of aPLs were the risk factors of APOs in women with APS. Treatment can significantly reduce the risk of adverse outcomes by upregulating platelet count during pregnancy in APS patients with thrombocytopenia.