ELEVATIONS OF AMNIOTIC-FLUID MACROPHAGE INFLAMMATORY PROTEIN-1-ALPHA CONCENTRATIONS IN WOMEN DURING TERM AND PRETERM LABOR

Objective: To determine whether elevated concentrations of macrophage inflammatory protein-1 alpha (MIP-1 alpha) in amniotic fluid (AF) are related to term and preterm labor. Methods: Amniotic fluid was obtaine d from women from five different clinical situations: 1) term cesarean delivery, no labor (n = 29); 2) normal term labor, no infection (n = 36); 3) preterm labor, delivery more than 1 week from sampling, no inf ection (n = 19); 4) preterm labor, delivery within 1 week from samplin g, no infection (n = 18); and 5) preterm chorioamnionitis (n = 8). Amn iotic fluid was collected aseptically at the time of amniocentesis, am niotomy, or hysterotomy. Concentrations of MIP-1 alpha were determined by enzyme-linked immunosorbent assay. Statistical analysis was by Wil coxon rank-sum test, Kruskal-Wallis test, and unpaired t test. Results : Women in normal term labor had significant elevations of AF MIP-1 al pha concentrations when compared with women at term undergoing repeat cesarean delivery (P <.001). In women with term gestation, AF MIP-1 al pha correlated well with cervical dilation (r(2) = 0.479, P <.001). In women with preterm labor who later delivered within 1 week of present ation, AF MIP-1 alpha concentrations were higher than those from women who did not deliver within 1 week. Women who presented with clinicall y evident chorioamnionitis had the highest concentrations of AF MIP-1 alpha (P =.001). Conclusion: Women in labor have significantly elevate d AF concentrations of MIF-1 alpha, particularly if labor is associate d with intrauterine infection. We suggest that MIP-1 alpha is involved in the physiology of normal labor and in the pathogenesis of infectio n-associated preterm labor.