Predictive Value of First-Trimester Serum TREM2 and SIGLEC1 Levels for Adverse Pregnancy Outcomes in Women with PCOS

Objective: To investigate the predictive value of first-trimester serum triggering receptor expressed on myeloid cells 2 (TREM2) and sialic acid-binding immunoglobulin-like lectin 1 (SIGLEC1) levels for adverse pregnancy outcome (APO) in pregnant women with polycystic ovary syndrome (PCOS), and to provide novel biomarkers for risk stratification management during pregnancy. Methods: This retrospective cohort study enrolled 380 singleton pregnant women with PCOS diagnosed between August 25, 2022, and January 25, 2025. Serum samples collected at gestational weeks 6-12 were retrieved from the biobank. TREM2 and SIGLEC1 concentrations were measured using ELISA. Participants were stratified into APO (n=117) and non-APO (n=263) groups. Receiver operating characteristic (ROC) curve analysis assessed predictive performance, and multivariable logistic regression identified independent risk factors. Results: Comparison of clinical data revealed that serum TREM2 and SIGLEC1 levels in the first trimester were significantly higher in the APO group than in the non-APO group (p < 0.05). Additionally, waist circumference, fasting plasma glucose (FPG), fasting insulin (FINS), and homeostatic model assessment for insulin resistance (HOMA-IR) were all significantly elevated in the APO group compared with the non-APO group (all p < 0.001). ROC analysis showed TREM2 achieved an area under the curve (AUC) of 0.828 (sensitivity 80.23%, specificity 75.21%) and SIGLEC1 yielded an AUC of 0.815 (sensitivity 83.65%, specificity 63.25%). The combined model demonstrated superior predictive accuracy (AUC 0.899, sensitivity 84.79%, specificity 82.05%). Multivariable logistic regression analysis demonstrated that elevated waist circumference (OR = 1.035, 95% CI: 1.010-1.060), HOMA-IR (OR = 2.027, 95% CI: 1.053-3.902), TREM2 (OR = 1.007, 95% CI: 1.005-1.009), and SIGLEC1 (OR = 1.006, 95% CI: 1.004-1.008) were all independent risk factors for APO in pregnant women with PCOS (all p < 0.05). TREM2 and SIGLEC1 levels positively correlated with HOMA-IR (r=0.202 and 0.231, respectively; both p < 0.001). Conclusion: Elevated serum TREM2 and SIGLEC1 levels in early pregnancy are associated with overall APO risk in PCOS patients, and their combined detection shows predictive potential; differential predictive values for specific outcome subtypes await further validation.