Amnionitis with Ureaplasma urealyticum or other microbes leads to increased morbidity and prolonged hospitalization in very low birth weight infants.

OBJECTIVE: To investigate the influence of culture proven intrauterine infection on preterm morbidity and to test the effect of antimicrobial treatment. METHODS: Retrospective cohort study conducted between October 1997 and February 2001 in patients with preterm premature rupture of membranes or preterm labor. Vaginal swabs were sampled and amniocentesis for microbiologic culture of the amniotic fluid was performed. Patients with Ureaplasma urealyticum in the amniotic fluid were treated with josamycin. Infants were followed post partum according to birth weight, gestational age, APGAR score and infant morbidity. RESULTS: In 49 eligible patients, 40% of cultures were positive, 22% for Ureaplasma urealyticum, 12% for other bacteria and 6% for candida. Children of mothers with positive amniotic fluid cultures had significantly lower gestational ages (26+4 weeks for Ureaplasma urealyticum [p=0.04] and 25+5 weeks for other microorganisms [p=0.0017] versus 28+6 weeks for mothers with negative amniotic fluid cultures) and lower birth weights (975 g [n.s.] and 828 g [p=0.0072] versus 1,041 g) but were appropriate for their gestational ages. 33.3% and 66.7% versus 24% of the children were mechanically ventilated [n.s.], duration of mechanical ventilation was 5.3 [p=0.02] and 10.1 days [p=0.04] versus 1.4 days, and prevalence of chronic lung disease was 38% and 33% versus 11% [n.s.]. Prevalence of severe intraventricular hemorrhage (12.5% [n.s.] and 33% [p=0.04] versus 3.4%) and nosocomial infections (50% for both groups of positive cultures versus 10.3% for negative cultures, p=0.02 and 0.03, respectively) was higher and median length of stay was significantly longer (121 [p=0.02] and 107 days [p=0.03] versus 60 days) in these patients. Maternal positive vaginal swab cultures were not associated with any of the above-mentioned factors. In none of the patients treated with macrolids for proven Ureaplasma urealyticum amnionitis could the microbes be eradicated. CONCLUSION: Maternal positive amniotic fluid cultures have been associated with lower gestational age and lower birth weight. Rate of infant morbidity was higher and length of stay was significantly longer in this group. Positive vaginal swabs were not predictive for infant morbidity. Treatment of mothers showing positive amniotic fluid cultures with macrolids was not effective.

Bacterial vaginosis as a risk factor for preterm delivery: a meta-analysis.

OBJECTIVE: We performed a meta-analysis to evaluate bacterial vaginosis as a risk factor for preterm delivery. STUDY DESIGN: Selection criteria were (1). the data appeared in original, published English-language reports of prospective studies or control groups of clinical trials that included women at <37 weeks of gestation with intact amniotic membranes, (2). all the women had to have been screened for bacterial vaginosis that was diagnosed by either clinical criteria or criteria that were based on Gram stain findings, and (3). the outcomes were preterm delivery, spontaneous abortion, maternal or neonatal infection, and perinatal death. RESULTS: Eighteen studies with results for 20,232 patients were included. Bacterial vaginosis increased the risk of preterm delivery >2-fold (odds ratio, 2.19; 95% CI, 1.54-3.12). Higher risks were calculated for subgroups of studies that screened for bacterial vaginosis at <16 weeks of gestation (odds ratio, 7.55; 95% CI, 1.80-31.65) or at <20 weeks of gestation (odds ratio, 4.20; 95% CI, 2.11-8.39). Bacterial vaginosis also significantly increased the risk of spontaneous abortion (odds ratio, 9.91; 95% CI, 1.99-49.34) and maternal infection (odds ratio, 2.53; 95% CI, 1.26-5.08). No significant results were calculated for the outcome of neonatal infection or perinatal death. CONCLUSION: Bacterial vaginosis, early in pregnancy, is a strong risk factor for preterm delivery and spontaneous abortion.

Antibiotic treatment of bacterial vaginosis in pregnancy: a meta-analysis.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of antibiotic treatment of bacterial vaginosis in pregnancy to reduce preterm delivery. STUDY DESIGN: We performed a meta-analysis of published, English-language, randomized, placebo-controlled clinical trials of antibiotic treatment of bacterial vaginosis in pregnant women with intact amniotic membranes at <37 weeks of gestation. Primary outcomes included preterm delivery, perinatal or neonatal death, and neonatal morbidity. RESULTS: Ten studies with results for 3969 patients were included. In patients without preterm labor, antibiotic treatment did not significantly decrease preterm delivery at <37 weeks of gestation, in all patients combined (odds ratio, 0.83; 95% CI, 0.57-1.21) nor in high-risk patients with a previous preterm delivery (odds ratio, 0.50; 95% CI, 0.22-1.12). In both groups, significant statistical heterogeneity was observed. A significant reduction in preterm delivery and no statistical heterogeneity were observed in 338 high-risk patients who received oral regimens with treatment durations of > or =7 days (odds ratio, 0.42; 95% CI, 0.27-0.67). Nonsignificant effects and no statistical heterogeneity were observed in low-risk patients (odds ratio, 0.94; 95% CI, 0.71-1.25) and with vaginal regimens (odds ratio, 1.25; 95% CI: 0.86-1.81). In one study antibiotic treatment in patients with preterm labor led to a nonsignificant decrease in the rate of preterm deliveries (odds ratio, 0.31; 95% CI, 0.03-3.24). CONCLUSION: The screening of pregnant women who have bacterial vaginosis and who have had a previous preterm delivery and treatment with an oral regimen of longer duration can be justified on the basis of current evidence. More studies are needed to confirm the effectiveness of this strategy, both in high-risk patients without preterm labor and in patients with preterm labor.

Production of oxytocin receptor and cytokines in primary uterine smooth muscle cells cultivated under inflammatory conditions.

OBJECTIVE: We studied the production of the oxytocin receptor and interleukins in human uterine smooth muscle cells cultured in vitro in the presence of cytokines that were shown to be elevated in gestational diseases such as intrauterine infections and chorioamnionitis. METHODS: Human uterine smooth muscle cells were cultured in the absence or presence of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), or lipopolysaccharide (LPS). Additionally, cells were cultivated under hypoxic conditions (3.5% oxygen). After 6, 12, 24, and 48 hours of incubation, oxytocin receptor mRNA was measured from total RNA using quantitative, competitive reverse transcriptase-polymerase chain reaction. Secreted cytokines (IL-1beta, IL-6, or IL-8) were quantitated from supernatants after 6, 12, 24, and 48 hours of stimulation by commercially available enzyme-linked immunosorbent assay. RESULTS: In nonstimulated cultures basal secretion of IL-1beta, IL-6, and IL-8 was detectable. Supplementation of IL-1beta induced a statistically significant decrease in oxytocin receptor mRNA abundance, whereas IL-6, TNFalpha, LPS, or hypoxia did not significantly affect oxytocin receptor gene expression. The cytokines IL-1 and TNFalpha induced IL-6 and IL-8 release, whereas secretion of the two interleukins was not altered in the presence of LPS or hypoxia. Expression of IL-1beta was not significantly induced under inflammatory or hypoxic culture conditions. CONCLUSION: The constitutive and cytokine-inducible expression of interleukins from uterine smooth muscle cells suggests that the myometrium may contribute to the overall production of inflammatory mediators in the uterus that are thought to govern term- or infection-induced preterm labor. Down-regulation of the oxytocin receptor under IL-1beta in myometrial cells may indicate that initiation and maintenance of labor could be partially limited under severe inflammatory conditions such as chorioamnionitis.