Difference of Maternal Serum Interleukin-8 in Preterm Labor and Normal Pregnancy

Objective This study was designed to investigate the difference of maternal serum interleukin-8 (IL-8) in preterm labor and normal pregnancy, to know the cut off point of maternal serum IL-8 in preterm labor and normal pregnancy, and also to evaluate the relative risk of preterm labor. Methods This study was conducted in analytical cross-sectional method within September 2010 May 2011. The inclusion sample was singleton pregnancy, within 28 37 weeks gestational age, cervical dilation 2 cm, and willing to join the study. Results There were 65 pregnant women, with 32 case of preterm labor and 33 control case of normal pregnancy or not in labor state. The subject characteristics such as maternal age, gestational age, and gravid status were not significantly different (p greater than 0.05). While the mean rate of maternal IL-8 in the preterm labor was 34.9834.79 and the mean rate of maternal IL-8 in the normal pregnancy was 11.413.32, and they were significantly different (t = 3.81 and p = 0.001). Based on the analysis using ROC curve, the cut off point was 15.30 pg/ml, with sensitivity 81.8 % and specificity 75 %. Based on that cut off point, there was significant difference between IL-8 among two group, with x2 = 21.104 and p = 0.001. The relative risk of preterm labor of maternal serum IL-8 greater than 15.30 pg/ml was 3-4 times (RR = 3.50, 95 % CI = 1.86 6.60). Conclusion This study showed that there were no difference of the sample characteristics, with significant differences of IL-8 value between the two groups. In the ROC curve, the cut off point was 15.30 pg/ml with sensitivity 81.8 % and specificity 75 %. Based on that cut off point value, the relative risk of preterm labor was 3 4 times (RR = 3.50, 95 % CI = 1.86 6.60). It could be concluded that high maternal serum IL-8 level in preterm pregnancy could induce the spontaneous preterm labor.