[Reference ranges of matrix metalloproteinase-1, -2, -9 and tissue inhibitor of matrix metalloproteinases-1 concentrations in amniotic fluid in physiological pregnancy].

The aim of this study was to determine reference values of matrix metalloproteinase-1 (MMP-1), MMP-2, MMP-9 and tissue inhibitor of matrix metalloproteinases-1 (TIMP-1) in the amniotic fluid at the first stage of labor in physiological pregnancy. 89 women at the first stage of term labor have been examined. Samples of amniotic fluid were taken at the first period of labor by vaginal amniotomy. Concentrations ofMMP-1, MMP-2, MMP-9, and TIMP-1 were investigated in amniotic fluid by ELISA kits. We have determined normal concentration ranges for MMP-1, MMP-2, MMP-9, TIMP-1, and ratios of concentrations of MMPs and TIMP-1 (MMP-1/TIMP-1, MMP-2/TIMP-1, MMP-9/TIMP-1) in the amniotic fluid at the first period of labor in physiological pregnancy. These included: MMP-1--5.1-16.8 pg/mg of protein, MMP-2--238.3-374.1 pg/mg of protein, MMP-9--66.1-113.3 pg/mg of protein, TIMP-1--4.7-13.6 pg/mg of protein, ratio of MMP-1/TIMP-1--0.1-2.2, ratio of MMP-2/TIMP-1--19.9-55.7, ratio of MMP-9/TIMP-1--4.2-17.2.

Métodos de indução do trabalho de parto / Methods of induction of labour

Os métodos de indução do parto podem ser divididos em estímulos naturais, estímulos exógenos diretos ou mecânicos e estímulos exógenos indiretos ou farmacológicos, cada qual apresenta suas particularidades nas indicações e contraindicações. O objetivo deste artigo foi realizar uma revisão da literatura consultando Medline/Pubmed e a Biblioteca Cochrane para avaliar a eficácia e segurança na utilização dos principais métodos de indução do trabalho de parto. Apurou-se não haver método ideal de indução do trabalho de parto. Os estímulos naturais e os métodos alternativos carecem de maiores estudos para incentivo de seu uso rotineiro. As prostaglandinas, em destaque o misoprostol, está indicada no Índice de Bishop desfavorável e a ocitocina em condições cervicais favoráveis. Os avanços no campo da biologia molecular tem corroborado que o método ideal deve atuar em sincronismo com a contratilidade uterina e a maturação cervical.(AU)

Methods of labor induction can be classified as natural stimuli, direct exogenous stimuli or mechanical and indirect exogenous stimuli or pharmacological. Which one has its peculiarities in relation to indications and contraindications. The objective of this article was to assess the efficacy and safety of the main methods of induction of labor trough the analysis of the medical literature in Medline/Pubmed and the Cochrane Library to. No ideal method of inducing labor was found. Further studies are required to encourage natural stimuli and alternative methods more often. According to Bishop scores, prostaglandins, (especially misoprostol) are unfavorable and oxytocin in case of favorable cervical environment. Advances in the field of molecular biology have confirmed that the ideal method should work simultaneously with uterine contraction and cervical ripening.(AU)

[Value of fetal scalp pH sampling early during the first stage of labour]. / Anomalies du RCF précocement au cours du travail : intérêt du pH au scalp.

OBJECTIVE: When fetal heart rate (FHR) abnormalities occur early during the first stage of labour, the risk of caesarean increases. In this study, we assessed the value of fetal scalp pH sampling on delivery mode, among women with FHR abnormalities before or at 5 cm cervical dilatation. METHODS: It is a retrospective observational study setting in a tertiary maternity center. All women with a live singleton cephalic fetus at term, who had a fetal scalp pH sampling, between January and July 2009, were included. We compared vaginal delivery and neonatal morbidity rates according to cervical dilatation at the time of the first fetal scalp pH sampling (≤ 5 or >5 cm). Neonatal morbidity was defined by pH at birth less or equal to 7.10 and/or 5 minutes Apgar score less or equal to 7 and/or neonatal transfer. RESULTS: During the study period, 108 women had at least one fetal scalp pH sampling, 8.5% of eligible women. Forty-six (42.6%) had a first pH at or before 5 cm cervical dilatation. The vaginal delivery rate was 62% and increased with increasing cervical dilatation at the time of the first fetal scalp pH (P<0.001). Among women who had fetal scalp pH early during the first stage of labour (≤ 5 cm), 50% delivered vaginally versus 71% when the fetal scalp pH was performed after 5 cm (P=0.026). The frequency of pH at birth less or equal to 7.10 was lower when the fetal scalp pH was performed before or at 5 cm (4.4% versus 16.9%, P=0.04). Neonatal morbidity rates were similar in both groups. CONCLUSION: In this study, when FHR abnormalities occur early during the first stage of labour, use of fetal scalp pH sampling allows a vaginal delivery in half of cases without an increase in neonatal morbidity.

Maternal and fetal oxidative stress and intrapartum term fever.

OBJECTIVE: The association between maternal chorioamnionitis and fetal oxidative stress has not been well established. STUDY DESIGN: A nested case control study was performed within a prospective cohort of term nulliparous women: 20 cases (intrapartum fever of >100.4 degrees F) and 20 afebrile controls. Oxidative stress was assessed using ThioGlo-1 (TG-1; Calbiochem, San Diego, CA) fluorescent sulfhydryl detection. Median levels (+/- interquartile range) of protein-thiol sulfhydryls were compared. RESULTS: In early labor, maternal oxidative stress (lower protein sulfhydryls) was significantly higher in those women who subsequently had intrapartum fever develop (79.87 +/- 22.88 vs 127.73 +/- 43.79 counts/second per microg protein; P < .001). In contrast, cord serum sulfhydryls were not different between groups (75.77 +/- 14.00 vs 75.04 +/- 17.83 counts/second per microg protein; P = .99) CONCLUSION: Our data suggest that the term human fetus is protected from maternal oxidative stress associated with intrapartum fever. However, maternal oxidative status in early labor is associated with subsequent intrapartum fever. Optimal fetal neuroprotection will require a more precise knowledge of pathogenic mechanisms.

Inflammatory cytokine mRNA detection by real time PCR in chorioamniotic membranes from pregnant women with preterm premature rupture of membranes.

OBJECTIVE: To quantify the expression of interleukin (IL)-1beta, IL-6, IL-8 and tumor necrosis factor alpha (TNF-alpha) in chorioamniotic membranes of PPROM pregnant women with chorioamnionits. STUDY DESIGN: The study included 25 PPROM women in labor, 15 PPROM without labor, and 25 pregnant women in preterm labor (PTL). Chorioamniotic membranes were collected for histopathological analyses and cytokine mRNA expression quantification by real time PCR. Comparisons were performed using the Mann-Whitney, Kruskal-Wallis, Fisher's exact test or z test with significance set at p<0.05. The software employed was the SigmaStat version 3.1. RESULTS: During the study PPROM incidence was 4.6% and chorioamnionits was present in 75% of the samples. IL-1beta, IL-6, and IL-8 mRNA expression did not statistically differ among study groups. TNF-alpha mRNA expression was statistically higher in PTL. No difference in the mRNA concentration of the cytokines studied in the presence of chorioamnionitis was observed. CONCLUSION: Chorioamniotic membranes are sources of IL-1beta, IL-6, IL-8, and TNF-alpha and their mRNA concentrations in PPROM are not related to the presence of chorioamnionitis.

Processes regulating cervical ripening differ from cervical dilation and postpartum repair: insights from gene expression studies.

A greater understanding of the processes that regulate cervical remodeling during pregnancy, parturition, and the postpartum period is required to understand causes of preterm and posterm birth in which abnormal cervical function is the primary culprit. In the current study, gene expression patterns unique to cervical ripening as compared with cervical dilation and/or postpartum repair are identified in a mouse model. Genes differentially regulated from gestation day 15 to late day 18 reveal processes important for cervical ripening. Genes differentially regulated from late day 18 to 2 hours after birth reveal processes that could be important during cervical dilation or the postpartum recovery period. Based on expression patterns, cervical ripening requires a downregulation of collagen assembly genes; increased synthesis of glycosaminoglycans that disrupt the matrix, such as hyaluronan; increased metabolism of progesterone; and changes in epithelial barrier properties. The latter phases of dilation and postpartum recovery are associated with increased assembly of mature collagen, synthesis of matrix proteins that promote a dense connective tissue, activation of inflammatory responses, prostaglandin synthesis, and further changes in epithelial barrier properties and differentiation. Processes/gene expression required for cervical ripening are distinct from those important in latter phases of cervical remodeling and highlight the importance of timing of tissue collection for understanding the molecular mechanisms of cervical ripening.

Protein C, protein S, and thrombomodulin in amniotic fluid. A preliminary study.

OBJECTIVES: The main components of protein C anticoagulant system are protein C (PC), protein S (PS) and thrombomodulin (TM); the system plays a protective role in pregnancy, mainly because it prevents the utero-placental circulation from local thrombosis. It is unknown whether the protein C anticoagulant pathway exists in amniotic fluid. The aim of the present study is to find out whether these three components are present in amniotic fluid. STUDY DESIGN: The study group consisted of 50 parturients with an uneventful pregnancy and birth and 25 non-pregnant controls. Amniotic fluid and blood were sampled at the end of the 1st stage of labor. PC, PS and TM were measured by immunoenzymatic method. RESULTS: All the samples of amniotic fluid contained measurable amounts of antigens of PC, PS and TM, although their concentrations were significantly lower than in the mother's blood: (i) The concentration of PC in amniotic fluid was 6.24+/-3.50% and PS 2.40+/-1.64%, while in the mothers' plasma it was 138.26+/-12.38% and 93.15+/-13.24%, respectively (P<0.0001). (ii) TM concentration in amniotic fluid constituted 63.92% of the concentration in the mother's blood (2.71+/-1.21 ng/mL vs. 4.24+/-0.88 ng/mL, P<0.001). CONCLUSION: Protein C, protein S and thrombomodulin are physiological constituents of the amniotic fluid. As their concentrations are low, it is reasonable to assume that they cannot counterbalance the procoagulant activity of amniotic fluid.

The Role of RCAS1 and oxytocinase in immune tolerance during pregnancy.

OBJECTIVES: To determine and compare the level of RCAS1 (receptor-binding cancer antigen expressed in SiSo cells) in placentas at term as well as oxytocinase/cystine amino peptidase (CAP) serum level a few days before labor in order to evaluate their possible role in the regulation of maternal immune response during pregnancy and in initiation of labor. METHODS: We estimated the RCAS1 content in 44 placental tissue samples, using Western blot method. We also assessed CAP serum level by its enzymatic activity, using L-cystine-di-beta-naphthylamide as a synthetic substrate. The statistical analysis was performed using Shapiro-Wilk procedure. Student's t test was applied to compare the differences between parametric data. A value of p < 0.05 was considered significant. RESULTS: RCAS1 was found in all placental tissue samples examined. The differences in the RCAS1 relative amount depended on the onset of labor, with the highest level in induced labor and the lowest in spontaneous labor. The differences were also observed in the CAP serum level with the highest level in pregnant women whose labor was induced. CONCLUSIONS: We have observed a link between the expression of the two proteins examined and the onset of the labor. Therefore, we posit that RCAS1 and CAP may play a role in the downregulation of the maternal immune response during pregnancy and may participate in the initiation of the labor.

Markedly elevated levels of inflammatory cytokines in maternal serum and peritoneal washing during arrested labor.

BACKGROUND: The role of inflammatory cytokines in the pathophysiology of arrested labor is currently unknown. We measured levels of inflammatory cytokines in maternal serum and peritoneal washings in arrested first stage of labor to assess the possible involvement of these mediators in this obstetric disorder. METHODS: This was a prospective, case-control study involving 15 women who underwent cesarean section for arrested cervical dilatation (group I), 15 controls who were operated during active labor for nonreassuring fetal heart-rate tracing (group II) and 15 controls who were operated electively (group III). Blood samples were drawn from all women shortly before the operation. The presence of peritoneal fluid was assessed and peritoneal washings were obtained during the operation. All samples were assayed for the inflammatory cytokines interleukin (IL)-1beta, IL-6, IL-8 and soluble IL-2 receptor (sIL-2R) by solid-phase enzyme-linked immunosorbent assay (ELISA). RESULTS: All women from group I and one patient (6.7%) from group II had some degree of peritoneal fluid accumulation, while none from group III had any. Serum samples from group I contained significantly higher IL-1beta, IL-6, IL-8 and IL-2R levels than both control groups. Peritoneal washings from group I contained significantly higher IL-1beta, IL-6 and IL-8 but similar IL-2R levels. CONCLUSIONS: Arrested first stage of labor is associated with peritoneal fluid accumulation and increased levels of inflammatory cytokines in both serum and peritoneal fluids. Inflammatory cytokines may therefore be involved in the pathophysiology of arrested labor.

Quantitation and localization of inflammatory cytokines interleukin-6 and interleukin-8 in the lower uterine segment during cervical dilatation.

PURPOSE: Cervical dilatation during parturition is associated with a significant increase of interleukin (IL)-6 and IL-8. The purpose of this study was to localize the respective messenger RNA and to quantitate their protein levels during various stages of dilatation. METHODS: Protein extracts from 34 biopsy specimens of the lower uterine segment at various stages of cervical dilatation (<2, 2 to <4, 4-6, and >6 cm) were subjected to enzyme linked immunosorbent assay for IL-6 and IL-8 to document their concentration. The respective mRNA expression was studied using reverse transcriptase PCR using IL-6 and IL-8 specific primers. Localization of IL-6 and IL-8 was done by in situ hybridization using biotinylated probes. RESULTS: The IL-6 and IL-8 concentrations increased significantly in the lower uterine segment tissues at 4-6 cm of dilatation. Expression of IL-8 was seen in all the tissues at or more than 4 cm dilatation, whereas IL-6 expression was inconsistent. In situ hybridization localized IL-6 and IL-8 mRNA to the glandular epithelium. CONCLUSIONS: The increase in the inflammatory cytokines (IL-6 and IL-8) during parturition is associated with cervical effacement.

Amniotic fluid concentrations of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 during pregnancy and labor.

OBJECTIVE: This study was undertaken to determine whether obstetric factors affect the concentrations of matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 in the amniotic fluid. STUDY DESIGN: We prospectively collected amniotic fluid samples from 109 women at various stages of pregnancy and labor and determined matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 concentrations by means of enzyme-linked immunosorbent sandwich assay systems. With multiple regression analysis we evaluated relationships between amniotic fluid matrix metalloproteinase 9 concentration and tissue inhibitor of metalloproteinase 1 concentration and the following factors: gestational age, presence of labor, cervical dilatation, membrane status, presence of clinical chorioamnionitis, and microbial colonization of the amniotic fluid. RESULTS: The detectable presence of amniotic fluid matrix metalloproteinase 9 was independently associated with intra-amniotic infection, labor, cervical dilatation, and spontaneous rupture of membranes. Chorioamnionitis and amniotic fluid matrix metalloproteinase 9 concentrations were correlated with tissue inhibitor of metalloproteinase 1 levels. CONCLUSIONS: Intra-amniotic infection, advanced labor, and rupture of membranes before the onset of labor were independently associated with the presence of matrix metalloproteinase 9 in the amniotic fluid. Both pathologic and physiologic processes appear to produce shifts in the balance between degradation and synthesis of the extracellular matrix.

Oxytocin secretion and human parturition: pulse frequency and duration increase during spontaneous labor in women.

The secretory pattern of oxytocin was determined in blood samples taken at 1-minute intervals for 30 minutes from 32 parturient women. The samples were collected in a manner that minimized degradation by plasma oxytocinase, and a highly specific antibody was used for the radioimmunoassay. The results indicated that oxytocin is secreted in discrete pulses of short duration. The frequency of the pulses was significantly higher during spontaneous labor than before the onset of labor. The mean pulse frequencies per 30 minutes were 1.2 +/- 0.54 before labor, 4.2 +/- 0.45 during the first stage, and 6.7 +/- 0.49 during the second and third stages of labor. The mean pulse durations in these three groups were 1.2 +/- 0.20, 1.9 +/- 0.28, and 2.0 +/- 0.26 minutes, respectively. The amplitude of the pulses was variable with no significant differences between the groups, the majority being around 1.0 microU/ml. The spontaneous pulses were of similar magnitude as those measured in 18 women after intravenous injections of 4 to 16 mU of oxytocin, which doses stimulated uterine contractions. We therefore conclude that the pulses of oxytocin observed at increasing frequency during spontaneous labor are of physiologic significance and provide evidence for the participation of oxytocin in the onset and maintenance of spontaneous labor.

Increased maternal plasma concentration of endothelin-1 during labor pain or on delivery and the existence of a large amount of endothelin-1 in amniotic fluid.

The concentration of endothelin-1 (ET-1) in plasma and amniotic fluid from normal pregnant women was determined by a sensitive sandwich-enzyme immunoassay system, established recently. The plasma ET-1 level increased gradually during normal pregnancy as the pregnancy advanced, the levels (0.40 +/- 0.02 pmol/l, n = 45) being significantly (p less than 0.05) higher after 29 weeks of gestation than those (0.32 +/- 0.01 pmol/l, n = 30) before 28 weeks of gestation. The plasma ET-1 level during labor pain was significantly higher (0.59 +/- 0.06 pmol/l, n = 10) than that (0.40 +/- 0.02 pmol/l, n = 45) in the 3rd trimester of pregnancy without labor pain (p less than 0.02). Moreover, a high level of ET-1 (17.38 +/- 0.25 pmol/l, n = 18) was detected in amniotic fluid on term delivery. The ET-1 level in amniotic fluid was significantly higher than the levels in maternal and umbilical cord plasma (p less than 0.001 and p less than 0.001, respectively). After delivery the maternal ET-1 level decreased gradually and 2 day postpartum ET-1 levels reached the normal non-pregnant level.

Amniotic fluid prostaglandin D2 in spontaneous and augmented labor.

Prostaglandin D2 (PGD2) was quantified in human amniotic fluid obtained from women in various phases of the first stage of spontaneous labor, augmented labor, and induced labor. PGD2 increased significantly only in late labor in the spontaneous and augmented labor groups.