Amniotic fluid gram stain and leukocyte count in the prediction of intrauterine infection in preterm prelabour amniorrhexis.

The purpose of the study was to examine the sensitivity and specificity of the amniotic fluid Gram stain and leukocyte count in the prediction of positive fetal blood and amniotic fluid cultures in 80 patients with preterm prelabour amniorrhexis. Amniocentesis and cordocentesis were performed and amniotic fluid and fetal blood were cultured for aerobic and anaerobic bacteria. Amniotic fluid was also cultured for Ureaplasma urealyticum and Mycoplasma hominis. The sensitivity of the Gram stain in the prediction of positive fetal blood and amniotic fluid cultures was 50 and 40% and the respective false positive rates were 12 and 4%. In the detection of aerobic or anaerobic infection of the amniotic fluid, the sensitivity and false positive rate of the Gram stain were 80 and 3% respectively. This compared favourably with the respective values of 66 and 35% for amniotic fluid leukocyte count > 30/mm3. Positive amniotic fluid Gram stain provides useful prediction of intra-uterine infection with aerobic or anaerobic organisms.