Hameed, C., Tejani, N., Verma, U. L., & Archbald, F. (1984). Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy. American journal of obstetrics and gynecology, 149(7), 726-730. https://doi.org/10.1016/0002-9378(84)90111-x
Hameed C, Tejani N, Verma UL, Archbald F. Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy. Am J Obstet Gynecol. 1984;149(7):726-730. doi:10.1016/0002-9378(84)90111-x
Hameed, Chaudhry, et al. "Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy." American journal of obstetrics and gynecology, vol. 149, no. 7, 1984, pp. 726-730.
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Thirty-seven consecutive patients with singleton pregnancies in "uncomplicated" preterm labor with intact membranes suitable for tocolysis were evaluated for evidence of silent chorioamnionitis by means of maternal serum C-reactive protein and amniotic fluid white blood cell count, Gram stain, and cultures. Abnormalities in these markers of infection were found to be significantly more common in cases that were refractory to tocolysis. These cases also showed both pathologic evidence of chorioamnionitis and a significantly greater neonatal early infectious morbidity. We conclude that silent chorioamnionitis is a significant cause of "uncomplicated" preterm labor refractory to conventional methods of tocolysis.
Subclinical intrauterine infection is an important cause of preterm labor, specifically where tocolysis has failed. Fifty patients in preterm labor with singleton pregnancies were studied prospectively to determine whether the presence or absence of C-reactive protein, a nonspecific marker for infection, would correlate with success or failure of tocolysis. Of the 50 patients, tocolysis failed in 11 of 15 women with a positive C-reactive protein determination. Tocolysis succeeded in 33 of 35 cases where C-reactive protein was negative (P less than .0005). Urinary tract infection occurred in 40% of the study patients, but was not a confounding factor in the interpretation of C-reactive protein.
Premature birth causes high rates of neonatal morbidity and mortality. There are multiple causes of preterm birth. This article reviews the evidence linking subclinical infection and premature birth. Although maternal genital tract colonization with specific organisms has been inconsistently associated with preterm birth and/or premature rupture of membranes, some infections have been consistently associated with preterm delivery. The association of histologic chorioamnionitis with prematurity is a consistent finding, but the mechanisms require further study. The relationship between histologic chorioamnionitis infection and the chorioamnionitis of prematurity requires additional research. A varying number of patients in "idiopathic" preterm labor have positive amniotic fluid cultures (0% to 30%), but it is not clear whether infection preceded labor or occurred as a result of labor. Evidence of subclinical infection as a cause of preterm labor is raised by finding elevated maternal serum C-reactive protein and abnormal amniotic fluid organic acid levels in some patients in preterm labor. Biochemical mechanisms for preterm labor in the setting of infection are suggested by both in vitro and in vivo studies of prostaglandins and their metabolites, endotoxin and cytokines. Some, but by no means all, antibiotic trials conducted to date have reported decreases in prematurity. These results support the hypothesis that premature birth results in part from infection caused by genital tract bacteria. In the next few years, research efforts must be prioritized to determine the role of infection and the appropriate prevention of this cause of prematurity.
The role of subclinical intrauterine infection in preterm labor was evaluated prospectively in 40 patients and appropriate control subjects. The 24 preterm labor patients (60%) with a negative C-reactive protein value responded to tocolysis 95.8% of the time, with a mean delay of delivery of 35.5 days and a mean gestational age of 36.9 weeks. The 16 patients (40%) with a positive C-reactive protein value responded to tocolysis only 37.5% of the time, with a mean delay of delivery of 14.4 days and a mean gestational age of 33.2 weeks. Pathologic evidence of chorioamnionitis was present in 32.9% of 310 preterm deliveries as compared to only 22.3% of 1631 term deliveries. The presence of subclinical infection must be considered in cases of preterm labor, especially among patients for whom tocolytic therapy is unsuccessful.
In this study we evaluated different markers of infection and their relationship to preterm delivery. Forty-four consecutive women with singleton pregnancies in uncomplicated preterm labor were investigated. C-reactive protein (CRP) in peripheral maternal blood, amniotic fluid cytokines, amniotic fluid leukocyte count, and amniotic fluid culture were performed in all patients. Thirty-six patients responded to standard tocolytic therapy and delivered after 34 weeks' gestation. In eight patients treatment failed and they delivered before 34 weeks' gestation. Two of these eight patients had a positive amniotic fluid culture for Ureaplasma urealyticum. The positive culture was accompanied by an elevated neutrophil count in the amniotic fluid. Elevated amniotic fluid levels of tumor necrosis factor (TNF) (more than 23 pg/mL), interleukin-6 (IL-6) (more than 2292 pg/mL) and interleukin-8 (more than 164 pg/mL) correlated with early preterm delivery. CRP levels in serum had a low sensitivity (38%) but a high specificity (94%) in predicting preterm delivery. This study indicates that preterm labor can be initiated by infection. Markers of infection obtained by amniocentesis have a better sensitivity and positive predictive value than noninvasive markers. Elevated IL-6 (more than 2292 pg/mL) seems to be the best predictor for preterm delivery, with a sensitivity of 75% and a specificity of 97%.
Tocolytics were administered in 66 consecutive women in uncomplicated preterm labour with intact fetal membranes (53 singleton and 13 twin pregnancies). C-reactive protein (CRP), a marker of infection, was determined daily and used retrospectively to investigate the role of subclinical infection in preterm labour and to predict the efficacy of tocolysis and the development of a clinical perinatal infection. CRP was also determined in 66 women in uncomplicated labour at term (53 singleton and 13 twin pregnancies). The placenta was examined for histological evidence of infection in all patients who were delivered before 36 weeks (n = 21) and in all women in the control group (n = 66). Elevated CRP levels were more often found in patients who were refractory to tocolysis, suggesting an underlying infectious morbidity. Placental infection was found in 62% of the preterm delivery group and in 12% of the control group. There was an association between elevated CRP levels and histological evidence of placental infection. However, confounding factors such as urinary tract infections limit the usefulness of the CRP test. Because CRP cannot predict clinical perinatal infection accurately, its clinical relevance is very limited.
Pregnancy › Preterm Birth › Infection and Inflammation · Birth and Delivery › Labor and Birth › Induction of Labor · General Gynecology › Infections › Vaginal and Cervical Infections
PMID 6465222 6465222 DOI 10.1016/0002-9378(84)90111-x 10.1016/0002-9378(84)90111-x Hameed et al. 1984, Hameed 1984
Cite this article
Hameed, C., Tejani, N., Verma, U. L., & Archbald, F. (1984). Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy. American journal of obstetrics and gynecology, 149(7), 726-730. https://doi.org/10.1016/0002-9378(84)90111-x
Hameed C, Tejani N, Verma UL, Archbald F. Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy. Am J Obstet Gynecol. 1984;149(7):726-730. doi:10.1016/0002-9378(84)90111-x
Hameed, Chaudhry, et al. "Silent chorioamnionitis as a cause of preterm labor refractory to tocolytic therapy." American journal of obstetrics and gynecology, vol. 149, no. 7, 1984, pp. 726-730.
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