Maternal plasma interleukin-6, interleukin-1β and C-reactive protein as indicators of tocolysis failure and neonatal outcome after preterm delivery

Objective. To investigate whether maternal serum interleukin-6 (IL-6), interleukin-1β (IL-1β) and high sensitive C-reactive protein (CRP) could be used as markers of tocolysis failure and adverse neonatal outcome in pregnancies with preterm labor (PL). Methods. Forty-seven maternal blood samples taken because of PL at admission and delivery were analyzed. Control samples were taken from 20 gravidas with normal pregnancies. Differences in interleukins and CRP levels with or without chorioamnionitis, connatal infection or periventricular leukomalacia (PVL) were analyzed. Cut-off values were estimated for prediction of tocolysis failure and adverse neonatal outcome. Results. All three parameters were significantly higher in patients delivering prematurely than in patients delivering at term. All three parameters were significantly higher with than without histologic chorioamnionitis (p < 0.001), with than without connatal infection (p < 0.01), with than without PVL (p < 0.01 for IL-6 and IL-1β, p < 0.05 for CRP), and in pregnancies with preterm premature rupture of membranes (PPROM) delivered within 48 hours compared to those more prolonged (p < 0.01). Choosing 50.9 pg mL of IL-6 and a CRP of 19.7 as cut-offs in maternal blood admission concentrations for neonatal PVL, resulted in sensitivity of 81% and specificity of 91% and sensitivity of 91% and specificity of 81%, respectively. At respective maternal blood admission cut-off levels of 27.8 pg mL of IL-6 and 8.9 of CRP, both parameters were effective predictors of connatal infection. Conclusions. Maternal blood IL-6 and CRP could become useful in predicting tocolysis failure and intrauterine treat for the fetus.