The Efficacy of C-Reactive Protein (CRP) to Albumin Ratio (CAR) and Fibrinogen to CRP Ratio (FCR) in Predicting the Latent Period of Preterm Labor

Objective: To investigate the role of inflammatory markers, including neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and monocyte to lymphocyte ratio (MLR), c-reactive protein (CRP) to albumin ratio (CAR), fibrinogen to albumin ratio (FAR), and fibrinogen to CRP ratio (FCR) in predicting the latency period (≤72 vs. >72 hours) before preterm birth.

Materials and methods: In a retrospective study, we assessed 135 patients meeting the specified criteria with signs of preterm labor (<34 weeks). The patients were categorized into two groups: 71 patients giving birth within 72 h (latency ≤ 72 h) and 64 patients giving birth after 72 h (latency > 72 h). We examined the demographic and medical characteristics and perinatal outcomes of all participants. Categorical variables between groups were compared using the Chi-square test. The Student's t-test was utilized for normally distributed continuous variables, and the Mann-Whitney U test was applied for non-normally distributed data. Receiver operating characteristic (ROC) curve analysis was conducted to identify the optimal cut-off levels for inflammatory markers in predicting the latency period before birth.

Results: Among the parameters examined, significant differences were observed between the groups only in terms of CAR and FCR. While CAR showed a significantly higher value in the group with latency period ≤72 h (0.537 ± 1.239 vs. 0.247 ± 0.325, p = 0.022), FCR showed a significantly lower value in the group with latency period ≤72 h (63.58 (2.99-1165) vs. 88.93 (9.35-1165), p = 0.013). The identified cut-off value for CAR was 0.190, providing a sensitivity of 57.7% and a specificity of 56.3% (p = 0.022). The cut-off value for FCR was 71.67, with a sensitivity of 42.3% and a specificity of 42.2% (p = 0.013).

Conclusions: The CAR and the FCR, serving as predictive markers for preterm labor, may offer a simple, cost-effective, and easily accessible approach, particularly in resource-limited settings.