Background: Missed miscarriage is defined by retention of a non-viable intrauterine pregnancy and may be associated with altered maternal inflammatory responses. Complete blood count (CBC)-derived inflammatory markers may serve as simple indicators of adverse early pregnancy outcomes. This study evaluated the utility of CBC-derived inflammatory
markers in first-trimester missed miscarriage.
Methods: This retrospective case–control study included 150 pregnant women: 50 with missed miscarriage and 100 with viable pregnancies. In both groups, the CBC used for analysis was obtained from medical records at 5-7 weeks of gestation. In the case group, missed miscarriage was diagnosed by ultrasound 2-5 weeks after CBC sampling. In the control group, women were recruited at the 13-week follow-up visit, where fetal viability was confirmed by ultrasound, and the earlier CBC obtained at 5-7 weeks was used for comparison. Women with major medical comorbidities or other conditions affecting inflammatory markers were excluded. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were calculated from CBC data.
Results: Mean NLR was significantly higher in the missed miscarriage group than in controls (3.45 vs. 2.80, P = 0.01). Mean PLR was also higher in the missed miscarriage group (161.2 vs. 125.0), with borderline statistical significance (P = 0.05), whereas LMR did not differ significantly between the two groups. In logistic regression analysis, only NLR was significantly associated with missed miscarriage (OR = 3.65, 95% CI 1.86–7.60). NLR showed the best discriminatory performance; at a cutoff value of > 4.6, it yielded 91% sensitivity and 82% specificity.
Conclusion: Elevated NLR was significantly associated with first-trimester missed miscarriage and showed the best discriminatory performance among the studied CBC-derived inflammatory markers. Larger prospective multicenter studies are needed before clinical application can be recommended.