F. Ghezzi

The tumor necrosis factor α and its soluble receptor profile in term and preterm parturition

Abstract Objective: The common terminal pathway of parturition describes the anatomic, biochemical, endocrine, and clinical events present in the fetus and mother in both term and preterm labor. Labor at term is thought to result from physiologic activation of this pathway, whereas preterm labor is the result of pathologic activating events. The purpose of this study was to determine whether physiologic and pathologic activation could be discerned by the analysis of a cytokine-receptor signaling system. Tumor necrosis factor α and its soluble receptors were used as probes because of their pivotal role in the regulation of several processes activated during parturition. Soluble receptors are thought to buffer the biologic and potentially deleterious effects of tumor necrosis factor α in pathologic conditions. Study Design: The in vivo concentrations of tumor necrosis factor α and its soluble receptors were studied in patients in term labor and preterm labor. Amniotic fluid was retrieved from 175 women and tumor necrosis factor α, tumor necrosis factor receptor 1, and tumor necrosis factor receptor 2 concentrations were measured by highly sensitive immunoassays. Patients were classified in the following groups: (1) term labor (n = 29), (2) term not in labor (n = 29), (3) preterm labor leading to term delivery (n = 34), (4) preterm labor without infection resulting in preterm delivery (n = 34), (5) preterm labor with intra-amniotic infection (n = 23), and (6) second trimester (n = 26). Results: Tumor necrosis factor α and tumor necrosis factor receptor 1 concentrations decreased with advanced gestational age ( r = –0.51 and r = –0.7; P 500 pg/mL vs median, 4.1 pg/mL; range, 1.1-22.7 pg/mL; P P P 500 pg/mL vs median, 4.8 pg/mL; range, 1-60.9 pg/mL; P P P 500 pg/mL) and its soluble receptors tumor necrosis factor receptor 1 (median, 8.8 ng/mL; range, 2.1-36.7 ng/mL) and tumor necrosis factor receptor 2 (median, 11.8 ng/mL; range, 3.4-46.3 ng/mL), concentrations that were significantly higher than in those with preterm labor who delivered at term and those who delivered preterm but were not infected. Conclusion: The tumor necrosis factor α and tumor necrosis factor α soluble receptor profiles are different in term and preterm parturition. Our observations provide support for the thesis that preterm parturition is a pathologic condition. Increased tumor necrosis factor α soluble receptor concentrations may attenuate the deleterious effects of the excess of tumor necrosis factor α found in pathologic labor. (Am J Obstet Gynecol 1999;181:1142-8.)

Maternal and perinatal outcome of patients with preterm labor and meconium-stained amniotic fluid

Objective To determine the clinical significance of meconium-stained amniotic fluid (AF) observed at amniocentesis in patients with preterm labor. Methods A nested case-control study was constructed based on the color of AF during amniocentesis. Forty-five women admitted with preterm labor and meconium-stained AF were matched for gestational age at admission and compared with 135 women with preterm labor and clear AF. All AF samples were cultured for aerobic and anaerobic bacteria and mycoplasma. Results The rates of positive AF cultures for microorganisms, overall preterm birth (before 36 weeks), preternt birth before 32 weeks, and clinical chorioamnionitis were all significantly higher in patients with meconium-stained AF than in those with clear AF (positive AF cultures, 38 versus 11%, P < .001; preterm delivery before 36 weeks, 73 versus 41%, P < .001; preterm delivery before 32 weeks, 51 versus 17%, P < .001; and clinical chorioamnionitis, 22 versus 6%, P = .003). In contrast, no significant differences were observed between groups with respect to maternal age, gravidity, parity, abruptio placentae, placenta previa, fetal distress, cesarean rate, or puerperal morbidity. Conclusion Patients with preterm labor and meconiumstained AF had higher rates of microbial invasion of the amniotic cavity, clinical chorioamnionitis, and premature deliveries than those with clear AF.

Meconium stained amniotic fluid in very low risk pregnancies at term gestation

OBJECTIVE To determine the prevalence and clinical significance of meconium stained amniotic fluid (MSAF) in a low risk population at term gestation and to investigate whether MSAF is a predictor for intrapartum and neonatal morbidity. METHODS A very low risk population including 37 085 consecutive deliveries at term composed the study population. A cross-sectional study was conducted and two groups of patients were identified according to the presence (n=6164) or absence (n=30921) of meconium in the amniotic fluid at delivery and the outcomes of the two groups compared. RESULTS The prevalence of MSAF was 16.6%. The incidence of cesarean section (5.6% vs 2.3% P<0.01), instrumental deliveries (3.2% vs 1.8% P<0.01), fetal distress (6.5% vs. 2.1% P<0.01), clinical chorioamnionitis (0.2% vs. 0.1% P<0.01), post-partum infection (0.5% vs. 0.2% P<0.01), 1-minute Apgar score <3 (1.9% vs. 1.1% P<0.01), small for gestational age (7.4% vs. 6.4% P<0.01). was significantly higher in the MSAF compared with the clear amniotic fluid group. Intrapartum and neonatal mortality in this low risk population was significantly higher in the MSAF group (1.7/1000) compared with women with clear AF (0.3/1000). CONCLUSIONS MSAF in a low risk population at term gestation is a predictor for adverse perinatal outcome and peripartum complications.

Intraamniotic infection in patients with preterm labor and twin pregnancies

Background. Microbial invasion of the amniotic cavity plays a major role in the pathogenesis of preterm labor and delivery in singleton pregnancy. Nevertheless, this association is not well established among patients with multiple gestations. The purpose of our study was to explore the role of intraamniotic infection in the setting of twin pregnancies.

Polyhydramnios is an independent risk factor for perinatal mortality and intrapartum morbidity in preterm delivery.

OBJECTIVE To investigate the clinical significance of polyhydramnios as a predictor of perinatal death and intrapartum morbidity in patients with preterm delivery. STUDY DESIGN The study population consisted of 4211 patients with singleton gestation, intact membranes and preterm delivery (< 37 weeks). Two groups were identified and compared according to the sonographic assessment of the amniotic fluid volume: increased and normal amniotic fluid. Analyses were conducted for the entire cohort as well as for the cohort excluding from each group all cases with congenital malformations. Logistic regression was used to assess the unique contribution of polyhydramnios to mortality and morbidity in the presence of other known risk factors. RESULTS The prevalence of polyhydramnios among women who delivered preterm was 5% (210/4211) including and 3.7% (142/3818) excluding the cases of congenital malformations, respectively. Polyhydramnios was associated with a higher rate of diabetes, large for gestational age neonates, fetal malpresentation at delivery, previous perinatal death and with a lower Apgar score at 1 and 5 min. Polyhydramnios was an independent predictor of perinatal mortality and intrapartum morbidity. When adjusted for well recognized risk factors for perinatal mortality and intrapartum morbidity (e.g. diabetes, severe pregnancy induced hypertension, multiparity, congenital malformation, previous perinatal death, low gestational age at delivery), the presence of polyhydramnios significantly increased the rate of perinatal mortality (odds ratio (OR) 5.8; 95% confidence interval (CI) 3.68-9.11) and of intrapartum morbidity (OR 2.8; 95% CI 1.94-4.03). CONCLUSION In the setting of preterm delivery, polyhydramnios is an independent risk factor for perinatal mortality and intrapartum complications even in the absence of congenital malformation and other conditions traditionally associated with increased perinatal mortality and morbidity.