Mid-trimester amniotic fluid interleukins (IL-1β, IL-10 and IL-18) as possible predictors of preterm delivery

Strong evidence implicates chronic intraamniotic inflammation in the etiology of preterm delivery. The purpose of this study was to determine whether amniotic fluid IL-1β, IL-10 and IL-18 concentrations in women undergoing mid-trimester amniocentesis can identify those at risk for preterm labor or preterm rupture of membranes.

A case-control study was conducted to compare mid-trimester concentrations of amniotic fluid IL-1β, IL-10 and IL-18 in women delivering at term or preterm. Out of 362 women included in the study, 38 presented with preterm labor. Thirty-eight women with term delivery, matched for chronological and gestational age served as controls. Women with abnormal fetal karyotypes or major anomalies were excluded. IL-1β, IL-10 and IL-18 concentrations were determined by ELISA. Conditional logistic regression was applied in the statistical analysis.

IL-1β was found to be positively and significantly associated with preterm delivery. Specifically, for every unit increase in IL-1β, women were on average 7.2 (OR: 7.2, CI: 1.94-26.77, p=0.003) times more likely to deliver preterm. IL-18 levels as well as gender were significantly associated with preterm delivery. Specifically, for every unit increase in IL-18, women were on average 1% less likely to have a preterm delivery (OR: 0.99, CI: 0.98-0.99, p=0.04). On the other hand, IL-10 was not significantly associated with preterm delivery.

Mid-trimester IL-1β concentrations are positively associated with preterm delivery. Therefore, IL-1β, determined on the occasion of mid-trimester amniocentesis could possibly serve as a marker of preterm delivery. In contrast, IL-10 and IL-18 concentrations are not elevated in mid-trimester amniotic fluid and probably cannot serve this purpose.