Arterial/venous thrombosis, fetal loss and stillbirth in pregnant women with systemic lupus erythematosus versus primary and secondary antiphospholipid syndrome: a systematic review and meta-analysis

BACKGROUND: We aimed to systematically compare arterial/venous thrombosis, fetal loss and stillbirth in pregnant women with systemic lupus erythematosus (SLE), primary anti-phospholipid syndrome (PAPS) and secondary anti-phospholipid syndrome (SAPS). METHODS: Online databases were carefully searched for relevant publications comparing SLE with PAPS and/or SAPS in pregnancy. Studies were included if: they compared SLE with APS [SLE versus PAPS or SLE versus SAPS or SLE versus PAPS and SAPS respectively] in pregnant women; and they reported specific adverse outcomes as their clinical endpoints including arterial/venous thrombosis, fetal loss and stillbirth. Risk ratios (RR) with 95% confidence intervals (CIs) were used as statistical parameters and the analysis was carried out by the RevMan 5.3 software. RESULTS: A total number of 941 pregnant women were included: 556 were candidates of SLE; 200 were candidates of PAPS; and 185 were candidates of SAPS. APS was associated with a significantly higher risk of fetal loss (RR: 4.49, 95% CI: 2.09–9.64; P = 0.0001). In addition, stillbirth and arterial/venous thrombosis were also significantly increased with APS (RR: 6.65, 95% CI: 2.14–20.60; P = 0.001) and (RR: 3.95, 95% CI: 1.28–12.16; P = 0.02) respectively. When patients with PAPS were compared with patients who suffered from SLE alone, fetal loss and arterial/venous thrombosis were still significantly higher with the former. When SAPS were compared with SLE (without anti-phospholipid antibodies), arterial/venous thrombosis, stillbirth and fetal loss were still significantly higher with SAPS. However, no significant difference was observed in arterial/venous thrombosis and fetal loss between PAPS and SAPS. CONCLUSIONS: PAPS and SAPS were associated with significantly higher arterial/venous thrombosis, fetal loss and stillbirth in comparison to SLE. However, no significant difference was observed when PAPS was compared to SAPS.