Background <p>Cervical insufficiency is a leading cause of late miscarriage and preterm birth, with high preterm birth rates even after cervical cerclage. Due to its retrospective diagnostic nature, clinical management remains controversial. This study aimed to evaluate clinical factors influencing gestational age prolongation and neonatal outcomes in second-trimester patients with cervical insufficiency, providing evidence for optimal treatment.</p> Methods <p>A retrospective analysis was conducted on the clinical data of 348&#xa0;second-trimester patients with cervical insufficiency. Univariate and multivariate analyses were applied to assess the effects of clinical factors on gestational age prolongation and neonatal outcomes.</p> Results <p>Multivariate analysis indicated that progressive elevation of blood cell count (OR = 0.487, 95% CI = 0.245–0.967), preterm premature rupture of membranes (PPROM) (OR = 0.280, 95% CI = 0.143–0.548), and progressive cervical shortening (OR = 0.120, 95% CI = 0.058–0.251) were independent risk factors for delivery before 34 weeks of gestation. In contrast, negative results of vaginal secretion re-examination (OR = 2.977, 95% CI = 1.209–7.331), residual cervical length of 10–20&#xa0;mm (OR = 2.917, 95% CI = 1.386–6.141), and diagnosis after 24 weeks of gestation (OR = 2.988, 95% CI = 1.52–5.874) were negatively associated with the risk of delivery before 34 weeks.</p> <p>With respect to gestational age prolongation, cervical cerclage performed before 24 weeks (β=0.249, 95% CI=14.099-31.168), residual cervical length ≥20 mm (β=0.172, 95% CI=8.011-24.910), and residual cervical length of 10-20 mm (β=0.001, 95% CI=4.830-19.632) were independently correlated with prolonged gestation. On the other hand, progressive elevation of blood cell count (β=-0.132, 95% CI=-19.507 to -5.561), progressive cervical shortening (β=-0.268, 95% CI=-30.259 to -15.561), diagnosis after 24 weeks of gestation (β=-0.106, 95% CI=-16.764 to -2.027), no re-examination of vaginal secretions (β=-0.213, 95% CI=-24.76 to -11.901), PPROM (β=-0.154, 95% CI=-21.825 to -7.452), and pathological chorioamnionitis (β=-0.148, 95% CI=-22.846 to -6.432) showed a negative correlation with gestational age prolongation.</p> <p>For neonatal outcomes, no re-examination of vaginal secretions (OR=0.252, 95% CI=0.123-0.517), infections in other systems (OR=0.343, 95% CI=0.141-0.833), progressive cervical shortening (OR=0.134, 95% CI=0.062-0.287), PPROM (OR=0.178, 95% CI=0.089-0.355), and chorioamnionitis (OR=0.208, 95% CI=0.096-0.449) were identified as independent risk factors for severe neonatal complications. Diagnosis after 24 weeks of gestation was negatively correlated with the risk of severe neonatal complications. Additionally, cortisol administration (HR=2.589, 95% CI=1.082-6.194), diagnosis after 24 weeks of gestation (HR=2.589, 95% CI=1.082-6.194), cervical cerclage performed before 24 weeks (HR=2.687, 95% CI=1.201-6.008), and cervical cerclage performed at ≥24 weeks (HR=7.140, 95% CI=1.877-27.169) were independently associated with improved neonatal survival rates.</p> <p>Progressive cervical shortening was confirmed as an independent risk factor for concurrent chorioamnionitis (OR=14.674, 95% CI=5.954-36.167), while twin pregnancy (a comorbidity) was negatively associated with the risk of pathological chorioamnionitis (OR=0.289, 95% CI=0.132-0.632). </p> Conclusions <p>Screening/treatment efficacy of vaginal secretions and monitoring blood counts reduce preterm birth &lt; 34 weeks and neonatal complications. Before 24 weeks, cerclage benefits those with progressive cervical shortening (≤ 10&#xa0;mm); after 24 weeks, the decision to perform emergency cerclage should be weighed against local neonatal care capacity. Prevention of chorioamnionitis infection should be emphasized for progressive cervical shortening during emergency cerclage.</p> Trial registration <p>This retrospective study was not prospectively registered.</p>