Maternal serum interleukin 6 and 8 and C-reactive protein in predicting the tocolytic therapy in preterm labor

This study aimed to evaluate the relation between C-reactive protein (CRP), interleukin (IL) 6 and 8 with the response to tocolytic therapy.

A total of 75 singleton pregnant women between 18 and 35 years old, and with symptoms of preterm labor were hospitalized in "Shahid Beheshti" hospital in Isfahan, Iran. Tocolysis in patients was performed first with infusion of 4 g of magnesium sulfate 20% and then 2 g per hour continued. Next, they were followed till delivery time to assess the response to the treatment. Baseline data and serum levels of IL-6 and IL-8 and CRP were all recorded.

A total of 16 patients with symptoms of preterm labor did not respond to the treatment and delivered prematurely and 59 women responded to tocolytic treatment and delivered at term. There was a significant relationship between serum IL-6, IL-8 and CRP levels with response to the treatment in cut-off > 45 for IL-6 [area under the curve [(AUC), 0.894; SE, 0.042; P-value < 0.0001, >171 for IL-8 (AUC, 0.864; SE, 0.059; P-value < 0.0001)] and >1.8 for CRP (AUC, 0.738; SE, 0.076; P-value = 0.001). Also, pairwise comparison of receiver operating characteristic curves between CRP, IL-6, and IL-8 showed that there were no significant differences between areas for IL-6 with IL-8 (P-value = 0.46); IL-6 with CRP (P-value = 0.086); and IL-8 with CRP (P-value = 0.18).

Maternal serum concentrations of IL-6 and IL-8 and CRP can be used as appropriate biomarkers for predicting the response to tocolytic therapy in pregnant women and there were no significant differences between these markers in predicting tocolytic therapy.