Accumulating evidence indicates an association between intraamniotic infection and raising concentrations of amniotic cytokines, resulting in preterm labor and preterm rupture of fetal membranes, because these cytokines are able to stimulate prostaglandin biosynthesis. Therefore the purpose of our study was to investigate if quantitative determination of Il-1 beta, Il-6, Il-8 and TNF-a in amniotic fluid may be a practicable method to diagnose intraamniotic infection. Since invasive amniocentesis doesn't allow repeated cytokine detection, in case of preterm rupture of fetal membranes, amniotic fluid also was obtained by placing a sterile gauze and cotton pad into the women's vagina, absorbing draining amniotic fluid for cytokine detection. Our results clearly indicate that Il-1 beta and TNF-a are not detectable in normal pregnancy, while Il-6 and Il-8 are produced in low, but constant levels. In contrast, in amniotic fluid of patients with intraamniotic infection high amounts of Il-6 and Il-8 were found, while Il-1 beta and TNF-a bioactivity became measurable, indicating that biosynthesis was activated. These results demonstrate, that infection associated cytokines detectable in amniotic fluid are highly sensitive markers for intraamniotic infection. In case of preterm rupture of fetal membranes recovery of amniotic fluid from a vaginal pad allows monitoring of cytokine bioactivity in daily intervals to control success of antibiotic treatment.