Interleukin-1 receptor antagonist in human cervicovaginal fluid in term pregnancy and labor.

OBJECTIVE

The objective of the study was to investigate temporal changes in interleukin-1 receptor antagonist (IL-1ra) in human cervicovaginal fluid (CVF) in term pregnancy and labor.

STUDY

DESIGN

CVF was collected weekly from 155 multiparous women from 36 weeks' gestation until labor. High vaginal swabs were collected for microbiology assessment.

RESULTS

IL-1ra was decreased in spontaneous term labor, compared with 15-21 and 22-28 days from labor, and was significantly lower at 0-7 days, compared with 15-21 days before labor (P < .05, 2-way ANOVA). After subdividing the women, IL-1ra concentrations were 6-fold lower in women who had prelabor rupture of membranes at term than women who had spontaneous labor with intact membranes at 8-14 and 15-21 days before labor (P < .05, Student t test). IL-1ra concentrations were not affected by the microbial status of the vagina.

CONCLUSIONS

The changes in IL-1ra concentrations observed in the CVF may be linked to the remodeling of fetal membranes leading to rupture.