Management of acute chorioamnionitis

Evaluation of gas-liquid chromatography for the rapid diagnosis of amniotic fluid infection: a preliminary report

Gas-liquid chromatography has been proposed as a possible tool in the rapid diagnosis of amniotic fluid infections. The analysis is based on the identification of specific organic acids derived from bacterial metabolism when organisms are present within the amniotic fluid. We retrospectively subjected 69 samples of amniotic fluid which had been obtained by transabdominal amniocentesis to analysis by gas-liquid chromatography. Forty-seven samples were derived from patients who either were in premature labor or had premature rupture of membranes with associated premature labor. Twenty-two specimens which served as a comparison group were obtained from patients who underwent amniocentesis for assessment of fetal maturity. The results obtained from chromatographic analysis are presented, and the possible applications of this technique to the clinical situation are discussed.

Clinical amniotic fluid infection and its effect on the neonate

This study was undertaken to determine the effects of clinical amniotic fluid infection on the neonate in terms of bacterial infection, hyaline membrane disease, asphyxia, and mortality. A retrospective chart review was made of 107 mothers with clinical amniotic fluid infection and their infants at this institution over a 3-year period. The next live-born infant with a birth weight within 100 gm and gestational age within 2 weeks was chosen as a control for each study patient. The rate of prematurity in the study group was 71%. When prematurity was controlled for, there was no significant difference in regard to asphyxia, hyaline membrane disease, bacterial sepsis, and death between the study and control groups. These findings suggest that the adverse outcome for infants delivered to mothers with clinical amniotic fluid infection at this institution was related primarily to their prematurity.

C-reactive protein as a predictor for chorioamnionitis in cases of premature rupture of the membranes

We evaluated C-reactive protein for its ability to predict the occurrence of clinical chorioamnionitis in 51 patients with spontaneous premature rupture of the membranes at less than or equal to 34 weeks of gestational age. All the patients had determinations of C-reactive protein on admission, and then 25 patients were tested daily. Of the total 51 patients, 14 developed clinical signs compatible with a diagnosis of chorioamnionitis. An analysis was conducted to compare the use of C-reactive protein to that of white blood cell count in predicting febrile disease. Our study indicates that C-reactive protein is an accurate and early marker for predicting clinical chorioamnionitis. White blood cell and differential counts are less accurate in such prediction, especially after steroid treatment.

Second-stage fetal tachycardia and neonatal infection

Forty fetuses who had mild or marked tachycardia during the final 10 minutes of the second stage of labor were evaluated for neonatal infection. Prolonged sepsis/pneumonia occurred in 10 of the 40 infants (25%), three of eight (38%) with marked tachycardia, seven of 32 (22%) with mild tachycardia, and in only one of 167 control infants who had a normal second-stage fetal heart rate (0.6%). None of the 40 women with fetal tachycardia or the 167 control subjects had any intrapartum fever or other evidence of acute chorioamnionitis. Persistent fetal tachycardia during the second stage of labor defines a population at increased risk for subsequent neonatal sepsis/pneumonia. This population will require prolonged, expert neonatal care.

Intra-amniotic bacterial colonization in premature labor

Bacterial culturing was performed on amniotic fluid obtained by transabdominal amniocentesis from 33 patients with singleton pregnancies who were in idiopathic premature labor with intact membranes prior to the thirty-fifth week of gestation. Bacteria were isolated in seven patients (21.2%). The patients who were at highest risk for intra-amniotic colonization were those who had two or more clinical parameters suspicious for intra-amniotic infection in a pregnancy prior to the thirtieth week. Anaerobic bacteria were isolated from all seven patients. Only one patient had mixed aerotolerance isolates. Anaerobic that were classified as significant pathogens were isolated in four patients. Three patients had isolates that grew on primary plates, and the rest were recovered only from broth. The greatest impact of intra-amniotic bacterial colonization in premature labor with intact membranes on perinatal outcome is expressed in extreme prematurity and appears to be a function of the pathogenicity and concentration of the offending organism(s).

The course of labor in term patients with chorioamnionitis

Labor records and internal fetal monitor tracings of 65 patients with uncomplicated term pregnancies who entered labor spontaneously and then developed chorioamnionitis were reviewed. Eighty-eight percent of patients were nulliparous. Seventy-five percent had abnormal labor, characterized by decreased uterine contractility, and 34% required cesarean delivery because of failure to progress in labor. The most common fetal heart rate abnormalities were diminished or absent variability (77%) and tachycardia (67%); 15% of the tracings had a sinusoidal pattern. Despite the high prevalence of abnormal fetal heart rate tracings, only one infant had a 5-minute Apgar score less than 7. It is concluded that chorioamnionitis has an inhibitory effect on labor. Compared to uninfected women, certain infected patients appear to require higher doses of oxytocin and greater uterine activity to effect a given change in cervical dilation.

Premature rupture of membranes: the role of C-reactive protein in the prediction of chorioamnionitis

A group of 52 patients with premature rupture of the membranes (PROM) before 34 weeks' gestation were evaluated prospectively and managed expectantly. Of 42 patients who were delivered of their infants, 26 (61.9%) had significant chorioamnionitis on histopathology, and 18 had positive microbial cultures at delivery. However, only seven patients (16.7%) developed clinical signs of chorioamnionitis. There were no maternal deaths or perinatal deaths attributable to sepsis. Only two infants (less than 5%) had positive blood cultures. All patients were assessed daily for the development of chorioamnionitis. Amniocenteses were not routinely performed. White blood cell counts, band neutrophil counts, and erythrocyte sedimentation rate determinations were found to be unreliable. C-reactive protein determinations were found most reliable with a high sensitivity and specificity. Elevated C-reactive protein levels correlated better with pathologic confirmation of chorioamnionitis than with the clinical febrile morbidity. Clinical implications for the management of PROM are discussed.

A prospective, controlled study of maternal and perinatal outcome after intra-amniotic infection at term

A study was made of the outcome for mothers and their neonates with both clinical and bacteriologic evidence of intra-amniotic infection at term. Samples of amniotic fluid from patients with intra-amniotic infection showed greater than 10(2) colony-forming units per milliliter of a high-virulence isolate, whereas samples from control patients showed no growth or low-virulence isolates only. Control patients were uninfected during labor and were matched on the basis of gestational age, interval from rupture of membranes to delivery, and mode of delivery. There were 67 matched pairs. The mean interval from diagnosis of intra-amniotic infection to delivery was 3.1 +/- 2.2 hours (+/- SD). Mothers with intra-amniotic infection had a significantly longer hospital stay and greater fever index after delivery than did control patients. Intrapartum bacteremia was documented in six of 50 (12%) women with intra-amniotic infection. The cesarean birth rate was 36%. There was one case of probable septic shock and one of postpartum hemorrhage among women with intra-amniotic infection. Infants in the intra-amniotic infection group had a significantly longer hospital stay than did the control infants. Among 59 infants for whom blood culture results were available, bacteremia was documented in five (8%) with intra-amniotic infection. Definite radiographic evidence of pneumonia was present in 4%; there were no cases of meningitis. There was one perinatal death in the intra-amniotic infection group. Overall, the maternal and perinatal outcome after intra-amniotic infection at term was excellent.

Amniotic fluid infection as determined by transabdominal amniocentesis in patients with intact membranes in premature labor

The rate of microbial infection of amniotic fluid among patients in premature labor with intact membranes and the effect of this condition on perinatal morbidity and mortality are not known. Two study this question, specimens of amniotic fluid were collected by transabdominal amniocentesis from 31 patients in premature labor with intact membranes. Microorganisms were isolated from 25% (8/31) of the specimens; 87% (7/8) of these mothers underwent delivery within 48 hours of amniocentesis, and 75% (6/8) of positive culture were from mothers who were never febrile. Perinatal morbidity was significantly greater among mothers with positive amniotic fluid cultures, as evidenced by earlier gestational age at delivery (31 vs. 36 weeks), lower newborn weight (1,740 vs. 2,613 grams), and longer hospitalization (39 vs. 9 days). A few simple, commonly available laboratory tests (amniotic fluid Gram stain, lactic dehydrogenase levels, and white blood cell count) appear to be useful in making a rapid diagnosis. The data suggest that the presence of microorganisms in the amniotic fluid of afebrile patients in premature labor with intact membranes represents an infectious process rather than an innocuous condition and raises questions with regard to current obstetric trends in the management of premature labor. The routine evaluation of similar patients by transabdominal amniocentesis is not recommended unless prospective studies can demonstrate a decrease in perinatal morbidity and mortality with this approach.

Bacterial contamination of the cervix and premature rupture of membranes

The endocervical flora was examined in 32 women with premature rupture of membranes (PROM). Sixty-six pregnant women served as controls. Ten patients with PROM who later developed chorioamnionitis were also included in the study. Samples for culturing were obtained from the endocervix on admission and at delivery and later from the fetal surface of the placenta. Blood for culturing was also taken in cases of chorioamnionitis. The total number of bacteria in the endocervix and placenta was higher in patients with PROM. Anaerobes were the most common, except for the fetal surface of the placenta, where aerobes were found in greater numbers. Cultures of blood from women with chorioamnionitis were positive in seven cases. These findings suggest that the high incidence of pathogenic or potentially pathogenic cervical bacteria in pregnancy is related to chorioamnionitis and PROM.