MATERNAL SERUM INTERLEUKIN-6 CONCENTRATION AS A MARKER FOR IMPENDING PRETERM DELIVERY

Objective: To determine whether serum interleukin-6 concentrations pre dict impending preterm delivery. Methods: Blood samples were collected from 130 gravidas at 22-34 weeks' gestation. The study group consiste d of 89 women evaluated for preterm contractions or premature rupture of membranes, and these women were compared with 41 outpatient control s without evidence of labor or infection, chosen by clinicians at the time of routine prenatal visits. Serum interleukin-6 concentrations we re measured using a specific enzyme-linked immunosorbent assay kit. An alyses were by the Mann-Whitney U and the Kruskal-Wallis tests. Result s: All 41 control subjects had serum interleukin-6 concentrations less than 8 pg/mL. Sixteen of the 89 study patients had serum interleukin- 6 concentrations greater than or equal to 8 pg/mL and 73 had values le ss than 8 pg/mL. When the serum interleukin-6 concentration was at lea st 8 pg/mL, the median interval from collection to delivery was signif icantly shorter than that among study and control subjects with serum interleukin-6 less than 8 pg/mL (5.5 versus 240 and 1801 hours, respec tively; P < .001). The median gestational age at delivery was signific antly lower when the serum interleukin-6 concentration was at least 8 pg/mL, compared with study and control subjects with serum interleukin -6 concentrations less than 8 pg/mL (29.6 versus 33.4 and 39.0 weeks, respectively; P < .001). In patients with preterm contractions, the in terval from collection to delivery was significantly shorter when the serum interleukin-6 concentration was at least 8 pg/mL than when it wa s less than 8 pg/mL (3 versus 600 hours, P < .001). Similarly, the med ian gestational age at delivery was significantly lower when serum int erleukin-6 was at least 8 pg/mL (29.0 versus 36.1 weeks, P < .001). Co nclusion: Maternal serum interleukin-6 concentrations appear to be ele vated in women destined to deliver prematurely. Measurement of this cy tokine may prove useful in treating patients at high risk for preterm delivery. (C) 1998 by The American College of Obstetricians and Gyneco logists.