The presence of amniotic fluid leukoattractants accurately identifies histologic chorioamnionitis and predicts tocolytic efficacy in patients with idiopathic preterm labor

OBJECTIVES: We tested these hypotheses: (1) that amniotic fluid from patients with idiopathic preterm labor and histologic chorioamnionitis contains leukoattractants and (2) that the detection of amniotic fluid leukoattractants is an accurate predictor of tocolytic efficacy. STUDY DESIGN: Amniotic fluid from 86 patients in idiopathic preterm labor was evaluated by microbiologic tests and leukotaxis assay. The tests' ability to predict histologic chorioamnionitis and response to tocolysis (51 tocolytic candidates) is established. Statistical analysis was performed with Fisher's exact test and unpaired Student t test. RESULTS: The detection of amniotic fluid leukoattractants was a better predictor of histologic chorioamnionitis (97%) than were amniotic fluid microbiologic tests (62%) ( p < 0.01). Also, in patients with detectable amniotic fluid leukoattractants tocolysis failed significantly more often than in patients without detectable leukoattractants (93% vs 7%, p < 0.01). CONCLUSION: The presence of leukoattractants in amniotic fluid detected by the leukotaxis assay accurately identifies histologic chorioamnionitis and can additionally predict tocolytic efficacy in patients with idiopathic preterm labor.