Subclinical Chorioamnionitis Research Articles

Amniotic fluid volume of third-trimester diamniotic twin pregnancies

To define the normal range of amniotic fluid (AF) volume in third-trimester diamniotic twin gestations. The AF volume of third-trimester diamniotic twin pregnancies was measured prospectively. An AF sample was drawn from both amniotic cavities of diamniotic twins either for diagnosis of subclinical chorioamnionitis with preterm labor and/or assessment of fetal lung maturity. Actual AF volume was determined in each amniotic cavity by a dye-dilution technique. The AF volume of 45 diamniotic twin pregnancies of 27-38 weeks' gestation was assessed. The AF volume per amniotic sac ranged from 155-5430 mL, with a mean (+/- standard deviation) of 877 +/- 860 mL. The AF volume in individual amniotic cavities and the total of both cavities in a diamniotic twin pregnancy were unchanged across the entire gestational age range (27-38 weeks). Neither fetal positioning within the uterus (lower twin versus upper twin) nor fetal weight were determining factors in the AF volume variability (P = .846 and P = .726, respectively). Based on absolute volumetric differences between the larger- and smaller-sac AF volume, we observed that as the AF volume of the larger sacs increased proportionately (P < .001), the AF volume of the smaller sacs remained relatively constant across the entire range of differences (P = .687) between 27-38 weeks. The average AF volume of 877 mL for each diamniotic twin is similar to the AF volume reported for third-trimester singletons. The AF volumes of diamniotic twin gestations relate neither to fetal position nor fetal weight, but instead develop independently without relation to the other amniotic cavity. Ninety percent of the AF volumes were 215-2500 mL.

Prematurity, Subclinical Intraamniotic Infection, and FetalBiophysical Parameters: Is There a Correlation?

Objective: This prospective study was undertaken to examine the effects of subclinical intraamniotic infection on fetal behavioral patterns. Methods: Amniotic fluid was obtained from four groups of patients (n = 99): group 1, patients with preterm premature rupture of the fetal membranes (PPROM) without infection; group 2, patients with PPROM and infection; group 3, patients with preterm labor (PTL) and without infection; and group 4, patients with PTL and infection. Fetal biophysical profiles were obtained on admission to the labor suite. Amniotic fluid was analyzed for the presence of microorganisms and endotoxin to confirm intraamniotic infection; cytokines interleukin (IL)-1β, IL-6, and IL-8 were also assayed. Results: We found no association between low scores for biophysical parameters and subclinical infection in patients with PPROM or PTL. Conclusions: We could not demonstrate that upon a patient's admission to the labor hall absent fetal breathing and absent fetal movement, as well as reactivity, correlate with subclinical intraamniotic infection. Elevated cytokines, i.e. IL-1β, IL-6, and IL-8 were associated with subclinical chorioamnionitis.

Doppler evaluation of the fetoplacental circulation in the latent phase of preterm premature rupture of membranes.

Blood velocity waveform analysis by pulsed Doppler ultrasonography in preterm premature rupture of membranes is described. Reduced amounts of amniotic fluid did not impair determination of the resistance indices from the umbilical artery. Good results were obtained from the internal carotid artery in 82% of cases. Failure in measurements at the internal carotid artery occurred when fetal head engagement prevented good study planes. Ninety-three percent of umbilical artery determinations fell within the normal limits for our control population as did 89.2% of those at the internal carotid artery. No differences in the resistance indices could be attributed to the length of the latent period in prematurely ruptured membranes or subclinical chorioamnionitis. Therefore, if a mother or fetus has an underlying condition that affects fetoplacental circulation, the resulting abnormal blood velocity waveform should reflect this condition rather than the effect of ruptured membranes.

Low Incidence of Positive Amnionic Fluid Cultures in Preterm Labor at 27-32 Weeks in the Absence of Clinical Evidence of Chorioamnionitis

In order to determine the utility of amniocentesis for detecting subclinical chorioamnionitis in asymptomatic afebrile women in preterm labor with intact membranes, we enrolled 47 women between 27-32 weeks' gestation in a prospective study. After enrollment, 38 women fulfilled all clinical and laboratory criteria for the study; nine women were excluded because they had a leukocyte count exceeding 15,000/microL. None of the 38 asymptomatic afebrile women had a positive culture from the amnionic fluid for bacteria, fungi, Mycoplasma hominis, Ureaplasma urealyticum, Chlamydia trachomatis, or any viruses. Sepsis was not proved in any of the 38 infants delivered to these patients. There was a clear relationship between histologic evidence of chorioamnionitis and failure of tocolytic therapy. Fetal lung profiles were mature in 29% of the amnionic fluid samples from 30-32 weeks' gestation, but in none of the amnionic fluid samples before 30 weeks. Amniocentesis does not seem useful to detect chorioamnionitis in asymptomatic afebrile women with preterm labor and intact membranes at 27-32 weeks' gestation, and should be reserved for those cases in which information about fetal lung maturity would be helpful.

Acute myometritis and chorioamnionitis during cesarean section of asymptomatic women

Postoperative endomyometritis develops in as many as 85% of women undergoing cesarean section, which is 10- to 30-fold higher than after vaginal delivery. The timing and mechanism by which the infecting organisms gain access to the uterine cavity are unclear. One possibility is that the infection may occur postpartum by ascending colonization of the wound. Alternatively, myometritis may be already present at the time the cesarean section is performed in asymptomatic patients. With tissue necrosis, the stage is then set for puerperal endomyometritis. To study this second alternative mechanism, myometrial and placental biopsy specimens were obtained in 91 asymptomatic patients at the time of cesarean section. Histologic evidence of chorioamnionitis was identified in 10% (991) of patients. Acute myometritis was present in 11% (1091) of the myometrial biopsy specimens. Seven of the nine women (77%) with subclinical acute chorioamnionitis demonstrated extension of the inflammation into the myometrium. Thirty-two percent (825) of women in labor and 31% (516) of those with rupture of membranes for >6 hours had acute chorioamnionitis or myometritis, which is significantly higher (p < 0.01) than in women without these risk factors. These findings suggest that approximately one third of asymptomatic women with rupture of the membranes for more than 6 hours or who are in labor at the time of cesarean section demonstrate histologic evidence of subclinical chorioamnionitis. In most of these patients the myometrium is also involved. The uterine incision is then performed through infected myometrium, possibly setting the stage for puerperal endomyometritis.