Pregnancy outcome predictors in antiphospholipid syndrome: A systematic review and meta-analysis

Objective: To identify and assess the magnitude of effect of pregnancy outcome predictors in women with antiphospholipid syndrome (APS) by means of systematic review and meta-analysis.

Methods: PubMed and Embase were searched (13th June 2020) for studies reporting on pre-pregnancy risk factors of pregnancy outcomes in APS patients. Literature screening and data extraction were conducted by two reviewers independently, in a blinded standardized manner. Pooled univariate odds ratios (OR) were computed using a random effects model. Heterogeneity was assessed by I²%.

Results: The search yielded 3013 unique results; 27 records were included in this meta-analysis. Previous thrombosis was associated with a decreased live birth risk (OR 0.60, p < 0.01, I² = 40%), increased neonatal mortality (OR 15.19, p < 0.01, I² = 0%), an increased risk of antenatal or postpartum thrombosis (OR 6.26, p < 0.01, I² = 0%) and an increased risk of delivering a small for gestational age neonate (SGA) (OR 2.60, p = 0.01, I² = 0%). Patients with an APS laboratory category I (double or triple positivity) profile had a decreased live birth risk (OR 0.66, p < 0.01, I² = 0%), an increased risk of SGA (OR 1.86, p = 0.01, I² = 43%) and preterm birth (OR 1.35, p < 0.01, I² = 49%). Triple positivity was associated with a decreased live birth risk (OR 0.33, p < 0.01, I² = 68%), an increased risk of preeclampsia (OR 2.43, p = 0.02, I² = 35%) and SGA (OR 2.47, p = 0.04, I² = 61%). Patients with lupus anticoagulant positivity had an increased risk of preeclampsia (OR 2.10, p = 0.02, I² = 48%), SGA (OR 1.78, p < 0.01, I² = 0%) and preterm birth (OR 3.56, p = 0.01, I² = 48%). Risk of bias assessment suggested considerable bias on study participation and statistical methods.

Conclusions: The results of this meta-analysis identified previous thrombosis, laboratory category I, triple positivity and lupus anticoagulant positivity as the most important predictors of adverse pregnancy outcomes. This up-to-date knowledge, can be used in preconception counseling and tailoring of obstetric care.