Investigating the predictive role of serum amyloid A and its association with immunological and coagulation biomarkers in recurrent pregnancy loss

To evaluate the predictive role of serum amyloid A (SAA) levels and their association with antiphospholipid antibodies (APA) and coagulation markers such as lupus anticoagulants (LA), anti-cardiolipin (ACA), protein C (PC) deficiency, protein S (PS) deficiency, and antithrombin III (ATIII) deficiency in recurrent pregnancy loss (RPL). This prospective case-control study comprised two groups: the study group (<i>n</i> = 88) included women with recurrent pregnancy loss at Mansoura University Hospital between January 2019 and December 2020, and the control group (<i>n</i> = 52) included women without obstetric or medical complications. Demographic, clinical, and laboratory data, including serum samples collected at 10 weeks of gestation, were collected from all participants. The study measured SAA levels, lupus anticoagulants, anti-cardiolipin, protein C, protein S, and antithrombin III levels. The SAA level was significantly elevated in the recurrent pregnancy loss group compared to that in the control group. Lupus anticoagulant positive, anti-cardiolipin positive Immunoglobulin M (IgM), and deficiencies in protein C, protein S, and antithrombin III were significantly observed in patients with RPL (<i>p</i> < 0.05). The SAA levels were significantly elevated in both LA-positive and ACA-positive IgM patients. The receiver operating characteristic (ROC) curve analysis demonstrated that at SAA > 24.8 for the prediction of recurrent pregnancy loss, sensitivity was 98.86%, and specificity was 92.31%. Positive and negative predictive values were 95.6% and 98.0%, respectively. The area under the curve = 0.971 (0.927-0.992). SAA is associated with recurrent pregnancy loss and may therefore serve as a potential predictor of this condition. The observed elevation in SAA levels could be primary or secondary to the inflammatory response that promotes thrombotic activity in RPL patients at risk of APA, Protein S, Protein C, and ATIII deficiencies. Implementing SAA screening during pregnancy may facilitate the identification of individuals who could potentially benefit from novel treatment strategies.