Intra-amniotic inflammation predicts microbial invasion of the amniotic cavity but not spontaneous preterm delivery in preterm prelabor membrane rupture

Objective. To predict microbial invasion of the amniotic cavity (MIAC) and spontaneous preterm delivery within seven days using a panel of selected proteins from amniotic fluid in a Swedish population of preterm prelabor membrane rupture (PPROM). Design. Prospective cohort study. Setting. Evaluation of intra-amniotic inflammation in preterm premature rupture of membranes. Population. Sixty-six pregnant women with preterm prelabor membrane rupture at 22+033+6 weeks gestational age. Methods. Twenty-seven amniotic fluid proteins were assayed by a multiple immunoassay. Main outcome measures. The intra-amniotic inflammatory response was evaluated according to the presence of MIAC and the risk of spontaneous preterm delivery within seven days. A prediction model was constructed using logistic regression. Results. The overall rates of MIAC and spontaneous preterm delivery within seven days were 20 and 50%, respectively. There was a higher inflammatory response in women with MIAC than in those without. Earlier gestational age at delivery and lower birthweight were observed in the presence of microbial invasion of the amniotic cavity. Amniotic fluid interleukin (IL)-6 and IL-10 were the best predictors of MIAC in terms of sensitivity (69%), specificity (81%), positive predictive value (47%), negative predictive value (91%) and a positive likelihood ratio of 3.6. There were no differences in intra-amniotic inflammatory response according to the risk of spontaneous preterm delivery within seven days. Conclusion. Amniotic fluid IL-6 and IL-10 are the best inflammatory biomarkers to predict MIAC in women with PPROM. Intra-amniotic inflammation does not predict the occurrence of spontaneous preterm delivery within seven days of PPROM.