In which preterm labor-patients is intravenous maintenance tocolysis effective?

AIM We evaluated whether maintenance tocolysis (intravenous ritodrine hydrochloride and/or magnesium sulfate) was effective in cases of spontaneous preterm labor with intact membranes. METHODS One hundred and thirty preterm labor patients who reached 36 weeks of gestation by maintenance tocolysis were selected. Immediate delivery (ID) after ceasing maintenance tocolysis was defined as an 'effective case'. The correlated factors between ID and no immediate delivery (NID) were statistically analyzed. RESULTS Thirty-six patients delivered < two days after ceasing maintenance tocolysis (27.7%) and were defined as effective cases. Multiple logistic regression analysis revealed that amniotic fluid interleukin-8 at admission (≥ 2.3 ng/mL; odds ratio [OR] 5.6, 95% confidence interval [CI] 2.1-17.6; P