Neutrophil elastase in amniotic fluid as a predictor of preterm birth after emergent cervical cerclage

Abstract

Introduction: The aim of this study was to investigate neutrophil elastase (NE) in amniotic fluid as a potential marker for predicting pregnancy continuation.

Material and methods: We enrolled 34 pregnant women with bulging fetal membrane during the second trimester who underwent emergent cerclage after confirming the absence of intrauterine infection (amniotic fluid glucose ≥15 mg/dL). Amniotic fluid NE levels were compared between women who completed and did not complete 30, 34, and 36 weeks of gestation, and the optimal cut-off value for predicting pregnancy continuation was estimated. Moreover, the differences in the duration of continued pregnancy were compared between women with NE levels above and below the optimal cut-off value.

Results: The optimal cut-off value for NE in amniotic fluid that predicted pregnancy continuation beyond 30, 34, and 36 weeks of gestation was 180 ng/mL; this cut-off value had a sensitivity, specificity, positive predictive value, and negative predictive value of 84.0, 77.8, 91.3, and 63.7% beyond 30 weeks of gestation; 87.5, 80.0, 91.5, and 72.3% beyond 34 weeks of gestation; and 85.0, 71.4, 80.9, and 76.9% beyond 36 weeks of gestation, respectively. The duration of continued pregnancy from emergent cerclage to delivery was significantly longer in women with amniotic fluid NE <180 ng/mL (95.1 ± 5.4 days) than in women with amniotic fluid NE ≥180 ng/mL (44.8 ± 14.3 days).

Conclusion: The NE levels in amniotic fluid may serve as a useful marker for predicting the duration of continued pregnancy after cervical cerclage.

Keywords: Amniotic fluid; cervical cerclage; glucose; neutrophil elastase; pregnancy; premature birth.