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PubMed2005

Comparison of transvaginal sonography with digital examination and transabdominal sonography for the determination of fetal head position in the second stage of labor.

OBJECTIVE: Precise determination of fetal head position in labor is a prerequisite for safe instrumental deliveries, and essential for the assessment of labor progress. Recent studies have cast serious doubts on the accuracy of the time-honored digital vaginal examination (DVE) in comparison to transabdominal ultrasound scans (TUS). However, transabdominal imaging is technically difficult with a deeply engaged fetal head in the second stage of labor. We examined the accuracy and time requirements of transvaginal scans (TVS) in the second stage of labor for determination of fetal head position. STUDY DESIGN: Sixty laboring women in the second stage of labor with a deeply engaged fetal head were examined by experienced nurse midwives and senior residents. Fetal head position was recorded as "time on a 12-hour clock." Subsequently, TUS and TVS were independently performed by a skilled sonographer. Accuracy and time requirements for all 3 examinations were recorded. RESULTS: Fetal head position could be determined in all cases by TVS, but not in 7 cases and 9 cases by DVE and TUS, respectively (P < .03; P < .008). A discrepancy of 60 degrees or more between the DVE and TUS or TVS was found in 13/60 cases (21.7%) and 14/60 cases (23.3%), respectively. A > or = 90 degrees discrepancy was found in 9/60 cases (15%) and 12/60 cases (20%), respectively (P < .02 for comparison of TUS and TVS). In 5 cases, the digital examination erroneously perceived an occiput posterior position as occiput anterior. No significant differences in fetal head position were detected between TUS and TVS, when the examination was technically feasible. The mean time (+/-SD) required for determining fetal head position was shortest for TVS (8.7 +/- 5.8 seconds) in comparison to DVE (22.7 +/- 14.6 seconds; P < .0001) or TAS (31.7 +/- 19.1 seconds; P < .0001). CONCLUSION: Transvaginal sonography was the most successful and accurate method for determination of fetal head position in the second stage of labor, and required the least time for performance. We believe that TVS should be routinely performed in the labor room setting for the determination of fetal head position.

Abdomen↗
PubMed2006

Temporal trends in the rates of trial of labor in low-risk pregnancies and their impact on the rates and success of vaginal birth after cesarean delivery.

OBJECTIVE: The national rate of vaginal birth after cesarean delivery decreased by 55% between 1996 and 2002. The objective of this investigation was to determine, in our population in upstate New York, whether this decline in the vaginal birth after cesarean delivery rate was due to temporal changes in the trial of labor rates or in the vaginal birth after cesarean delivery success rates. STUDY DESIGN: Regional perinatal databases were used to obtain birth certificate data from a total of 135,833 live births in upstate New York from 1998 to 2002. Trial of labor, vaginal birth after cesarean delivery, and vaginal birth after cesarean delivery success rates were calculated for the 11,446 women who had had a previous cesarean delivery and a singleton, low-risk pregnancy at > or = 37 weeks of gestation. Additional factors that were analyzed included age, race, education, insurance, body mass index, parity, gestation, area of residence, prenatal care provider, size of hospital, and level of newborn nursery specialization. Tests for trends were conducted by year for each of the variables. RESULTS: The trial of labor rate declined 39% from 58.7 in 1998 to 35.7 per 100 eligible women in 2002 (P < .01). The decline in trial of labor rates persisted after stratification within almost all groups (P < .01). The overall vaginal birth after cesarean delivery rate decreased 44%, from 42.7 in 1998 to 24.1 per 100 eligible women in 2002 (P < .01). The decline in vaginal birth after cesarean delivery rates persisted after stratification within almost all groups (P < .01). The rate of vaginal birth after cesarean delivery success was unchanged from 1998 to 2002 (P = not significant). CONCLUSION: We found a major decline in trial of labor and vaginal birth after cesarean delivery rates in low-risk women from 1998 to 2002. There was no change in vaginal birth after cesarean delivery success in those patients who attempted trial of labor. This suggests that the decline in the vaginal birth after cesarean delivery rates that have been observed nationally may be due to a decline in trial of labor attempts and not to a change in vaginal birth after cesarean delivery success rates. The steep declines in trial of labor attempts and vaginal birth after cesarean deliveries suggest that there was a rapid change in the perception of optimal treatment practices for these patients by obstetricians.

Adult↗
PubMed2006

The MFMU Cesarean Registry: impact of fetal size on trial of labor success for patients with previous cesarean for dystocia.

OBJECTIVE: The purpose of this study was to determine the influence of change in infant birth weight between pregnancies on the outcome of a trial of labor for women whose first cesarean delivery was performed for dystocia. STUDY DESIGN: Secondary analysis of 7081 patients with 1 previous cesarean delivery and no other deliveries after 20 weeks' gestation, undergoing a trial of labor with a singleton gestation. Cases were classified as dystocia if the listed indication for the cesarean delivery in the first pregnancy was failed induction, cephalo-pelvic disproportion, failure to progress, or failed forceps or vacuum. Outcomes of the trial of labor were correlated with fetal size relative to birth weight in the initial pregnancy for those women whose initial cesarean delivery was for dystocia and those with other indications. RESULTS: For the cohort being studied (n = 7081), dystocia was the indication for the first cesarean delivery for 3182 (44.9%). Trial of labor resulted in vaginal delivery for 54% of patients whose first cesarean delivery was performed for dystocia, compared with 67% for those with other indications (P < .01). For those whose first cesarean delivery was for dystocia, trial of labor success was correlated with birth weight differences between the pregnancies, with only 38% delivering vaginally if the trial of labor birth weight exceeded the initial pregnancy birth weight by more than 500 g. Using logistic regression and adjusting for other potential confounding factors, the odds of success decreased by 3.8% for each increase of 100 g in birth weight in the trial of labor relative to the first birth weight. CONCLUSION: For women with previous cesarean delivery for dystocia, increasing birth weight in the subsequent trial of labor relative to the first birth weight diminishes the chances of successful vaginal delivery.

Adult↗
PubMed2006

Preterm labor is induced by intraamniotic infusions of interleukin-1beta and tumor necrosis factor-alpha but not by interleukin-6 or interleukin-8 in a nonhuman primate model.

OBJECTIVES: The purpose of this study was to determine the relative contributions of individual proinflammatory cytokines and chemokines to the triggering of preterm labor. STUDY DESIGN: Eighteen chronically instrumented pregnant rhesus monkeys at 135 +/- 3 days gestation (term = 167 days) received 1 of 5 intraamniotic infusions: (1) interleukin-1beta (IL-1beta) (10 microg; n = 5), (2) tumor necrosis factor-alpha (TNF-alpha) (10-100 microg; n = 5), (3) IL-6 (20 microg twice a day; n = 2), (4) IL-8 (20 microg twice a day; n = 2), and (5) saline control (n = 4). Primary study outcomes were the mean uterine hourly contraction area (mm Hg x s/h) in 24 hours during peak response to cytokine infusion (all groups) and the interval from cytokine infusion until labor onset (IL-1beta, IL-6, and IL-8 groups). Secondary outcomes were quantities of amniotic fluid cytokines and chemokines (IL-1beta, TNF-alpha, IL-6, and IL-8), prostaglandins E2 and F2alpha, leukocytes, and matrix metalloproteinase-9 (MMP-9). Histopathology of fetal lungs and placental membranes was assessed. RESULTS: IL-1beta stimulated the most intense contraction patterns, resulting in preterm labor in all cases. TNF-alpha induced a variable degree of uterine activity among individual animals stimulating either preterm labor (n = 2) or a uterine contraction pattern of moderate intensity (n = 3). Despite prolonged elevations in amniotic fluid levels, neither IL-6 nor IL-8 induced preterm labor or an increase in uterine activity until near term. The mean interval from the initiation of IL-6 and IL-8 infusion to the onset of labor was significantly longer than after IL-1beta (21.9 vs 1.1 days; P < .01), and did not differ from the saline control group (27.6 days; P = NS). Intraamniotic infusion of IL-1beta or TNF-alpha was associated with significant elevations in all tested amniotic fluid cytokines, IL-8, prostaglandins, MMP-9 and leukocytes compared with gestational age-matched saline controls. IL-6 and IL-8 infusions were not associated with increases in IL-1beta or TNF-alpha and only produced a moderate increase in amniotic fluid prostaglandins. All cytokine infusions induced histologic chorioamnionitis and an accumulation of neutrophils in fetal lungs. CONCLUSION: Preterm labor was induced by intraamniotic infusions of IL-1beta and TNF-alpha, but not by IL-6 or IL-8 although inflammatory changes in fetal membranes and lungs were uniformly present. Our results indicate a primary role for IL-1beta and TNF-alpha in the triggering of preterm labor associated with inflammation or infection.

Amniotic Fluid↗
PubMed1981

A simpler approach to labor induction using lipid-based prostaglandin E2 vaginal suppository.

The outcome of labor induced by use of a glyceride-based vaginal suppository of prostaglandin E2 (PGE2) inserted 3 hours before amniotomy, when the cervix is favorable, has been assessed. Using 5 mg PGE2 for primigravidas and 2.5 mg for multigravidas, 63% of the former and 81% of the latter established labor and were delivered of their infants without oxytocin augmentation, allowing ambulation during early labor. No maternal complications were detected as a result of the PGE2 treatment. Compared with patients undergoing conventional induction by amniotomy and immediate oxytocin titration there was no difference in the duration of labor, with a few patients establishing labor and giving birth quickly with both induction methods. Fetal distress was less common following PGE2 treatment than following conventional induction, with three patients in each group requiring delivery by cesarean section. Cephalopelvis disproportion in the second stage of labor requiring cesarean section to deliver occurred more frequently in the prostaglandin-treated group, possibly as a result of reduced upper segment contractility in the first stage of labor with subsequent poor fetal head molding. Epidural analgesia and postpartum hemorrhge were both reduced following PGE2-induced labor.

Adult↗
PubMed1987

Arachidonate lipoxygenase metabolites in amniotic fluid of women with intra-amniotic infection and preterm labor.

This study was undertaken to examine the effects of intrauterine infection and preterm labor on the amniotic fluid concentrations of arachidonate lipoxygenase metabolites in women with premature rupture of membranes. Amniotic fluid was obtained from four groups of women with premature rupture of membranes: group 1, women without labor or infection; group 2, women with labor but without infection; group 3, women with intra-amniotic infection but without labor; and group 4, women with both infection and labor. 12-Hydroxyeicosatetraenoic acid, 15-hydroxyeicosatetraenoic acid, and leukotriene B4 were measured by radioimmunoassays. Amniotic fluid concentrations of 12-hydroxyeicosatetraenoic acid were found not to differ significantly among the four groups. Amniotic fluid concentrations of 15-hydroxyeicosatetraenoic acid in group 4 were significantly higher than in women in groups 1 and 3 (p less than 0.05). In addition, amniotic fluid concentrations in leukotriene B4 were significantly higher in group 4 than in any of the other three groups (p less than 0.05). Leukotriene B4 concentrations were higher in groups 2 and 3 than in group 1, suggesting that the presence of both labor and infection increases the concentration of this metabolite in amniotic fluid. Infection and labor had an additive effect in the elevation of amniotic fluid concentrations of leukotriene B4. These results suggest that the amniotic fluid concentrations of arachidonate lipoxygenase metabolites are affected differently by the presence of infection and labor in women with premature rupture of membranes.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1994

Expression of the gap junction protein connexin-43 is increased in the human myometrium toward term and with the onset of labor.

OBJECTIVES: Our aim was to determine the temporal pattern of expression of transcripts encoding the myometrial gap junction protein connexin-43 in the human myometrium during late pregnancy and with the onset of labor. We also correlated these data with levels of total connexin-43 protein and the appearance of gap junctions within the myometrial cell membrane. STUDY DESIGN: Myometrial tissue was collected during cesarean section from 27 women between 37 and 41 weeks of gestation not in labor and from 7 women between 39 and 41 weeks during active labor. The levels of connexin-43 messenger ribonucleic acid and protein were estimated by Northern and Western analysis, respectively. The appearance of gap junctions between myometrial cells was assessed by immunofluorescence of histologic sections of myometrium from these women. RESULTS: Levels of connexin-43 messenger ribonucleic acid in myometrial tissue collected from women not in labor increased (p < 0.01) between 37 and 40 weeks' gestation with a further significant increase occurring during labor (p < 0.05). The level of connexin-43 protein decreased (p < 0.05) during late pregnancy and was not increased during labor although gap junctions (which were not present during pregnancy) did appear in the myometrial cell membrane during labor. CONCLUSIONS: These data suggest that the mechanisms responsible for the increased myometrial cell-cell communication necessary for the development of effective labor contractions likely involves regulation at the level of both messenger ribonucleic acid and gap junction formation in the cell membrane.

Animals↗
PubMed1996

The effect of changes in atmospheric pressure on the occurrence of the spontaneous onset of labor in term pregnancies.

OBJECTIVE: Our purpose was to determine whether there is a relationship between changes in atmospheric pressure and spontaneous onset of labor in term pregnancy. STUDY DESIGN: All women admitted to Medical Center of Central Massachusetts-Memorial Hospital with spontaneous onset of labor at term and who were delivered on the service during a 12-month period represent the cohort for this study. Each maternal chart was abstracted to ensure that each member of the cohort met the inclusion criteria. Hourly recordings of atmospheric pressure made at the Worcester Station of the National Weather Service, Department of Commerce, were used as the meteorologic data points of interest. Least-squares regression was used to determine an equation that expresses the probability of the onset of labor in this cohort as a function of gestational age, which was used to calculate expected numbers for the statistical analyses. Two relationships were studied: (1) the ratio of the observed to the expected number of onsets of labor and (2) the initiation of labor and atmospheric pressure changes in the preceding 3 hours. RESULTS: Three-hour periods of falling atmospheric pressure were less often followed by initiation of labor than were the periods with other types of pressure sequences. No association was observed between the onset of labor and days of low mean pressure. CONCLUSION: Although there was an observed statistically significant association between falling barometric pressure and onset of labor, the magnitude of the difference is not of clinical significance.

Atmospheric Pressure↗
PubMed2002

Induction of labor in twin pregnancy after 36 weeks does not increase maternal-fetal morbidity.

OBJECTIVE: To compare maternal and perinatal outcomes in twin pregnancy patients without any fetal or maternal disease, managed by labor induction or expectant management after 36 weeks gestation. METHODS: We conducted a case-control study of 81 patients: labor induction (n=36) vs. expectant management (n=45). Labor was induced using oxytocin (n=18), vaginal prostaglandins (n=6) or intrauterine balloon catheter (n=12) according to the Bishop score. Maternal and perinatal outcome variables were compared among both groups. RESULTS: The characteristics of the labor induction group and the expectant management group were not statistically different, except for the rate of nulliparae (55.6% vs. 33.3%) and the rate of epidural analgesia (100% vs. 80%). There was no significant difference in labor time (6.5+/-2.8 h vs. 6.0+/-3.6 h), cesarean section rate (8.3% vs. 13.3%) or duration of maternal hospitalization (7.3+/-2.0 days vs. 7.5+/-2.3 days) in the labor induction group and in the expectant management group, respectively. The birth weight was higher in the labor induction group than in the expectant management group (2639+/-352 g vs. 2463+/-298 g, P<0.001). The rate of Apgar score <7 at 5 min was 0% and 3.3%, respectively. Neonatal intensive care unit admission occurred in 30.5% and 26.6% of the groups, respectively. No perinatal death was reported. CONCLUSION: Induction of labor may be proposed to patients with uneventful twin pregnancy after 36 weeks gestation without increasing maternal-fetal morbidity.

Apgar Score↗
PubMed2000

Membrane sweeping in conjunction with labor induction.

OBJECTIVE: To determine whether cervical membrane sweeping (stripping) during induction of labor is beneficial. METHODS: We compared outcomes of labor after induction in pregnant women at term in a randomized trial. Women were assigned to having their membranes swept or not during induction. Outcome measures included duration of labor, maximum dose of oxytocin used, induction-labor interval, and mode of delivery. RESULTS: We recruited 130 nulliparas (64 sweep, 66 nonsweep) and 118 multiparas (60 sweep, 58 nonsweep). Among nulliparas who received intravaginal prostaglandin (PG) E(2) and oxytocin, those who had simultaneous sweeping had significantly shorter mean (+/- standard error of mean) induction-labor interval (13.6 +/- 1.4 versus 17.3 +/- 1.2 hours, P =.048), lower mean maximum dose of oxytocin (6.8 +/- 0.8 versus 10.35 +/- 1.1 mU/minute, P =.01), and increased normal delivery rates (vaginal delivery 83. 3% versus 58.2%, P =.01). Sweeping also had a favorable effect on nulliparas who received oxytocin alone (mean induction-labor interval 5.8 +/- 3.1 versus 11.2 +/- 3.6 hours, P =.04; mean maximum dose 8.8 +/- 1.3 versus 16.3 +/- 1.9 mU/min, P =.01). Those differences were limited to women with unfavorable cervices. There were no differences in any outcome measures in multiparous women. CONCLUSION: Sweeping of the membranes during induction of labor had a beneficial effect on labor and delivery, which appeared to be limited to nulliparas with unfavorable cervices who needed cervical priming with PGE(2).

Adult↗
PubMed1998

Umbilical venous D-dimer concentrations with and without labor.

OBJECTIVE: To determine if labor activates the fetal fibrinolytic system. METHODS: A total of 59 umbilical venous blood samples were collecting following vaginal delivery at term (n = 20), cesarean delivery following labor at term (n = 12), vaginal delivery before term (n = 18), and cesarean delivery without labor (n = 9). D-dimer concentrations, a sensitive marker of fibrinolysis, were measured by enzyme-linked immunosorbent assay, and compared between groups by Kruskel-Wallis and Mann Whitney U tests, with significance defined as P < .05. RESULTS: There were no significant differences in median D-dimer concentrations between newborns delivered vaginally or by cesarean after term labor or preterm labor. There were significant differences in median umbilical venous D-dimer concentrations in subjects delivered vaginally or by cesarean after term or preterm labor compared with term subjects without labor delivered by cesarean (427, 773, and 326 versus 87 ng/mL, P = .01). CONCLUSION: Elevation of umbilical plasma D-dimer concentrations in laboring patients suggests activation of fetal fibrinolysis before delivery.

Adult↗
PubMed1999

Active-phase labor arrest: oxytocin augmentation for at least 4 hours.

OBJECTIVE: To assess a labor-management protocol that mandated at least 4 hours of oxytocin augmentation before cesarean delivery for active-phase labor arrest. METHODS: We prospectively evaluated term gravidas in spontaneous labor with active-phase labor arrest (cervix at least 4 cm dilated and 1 cm or less of cervical progress in 2 hours). Exclusion criteria included nonvertex presentation, previous cesarean, multiple gestation, and a nonreassuring fetal heart rate tracing or chorioamnionitis at the time of labor arrest. After the diagnosis of active-phase arrest, oxytocin was initiated with an intent to achieve a sustained uterine contraction pattern of greater than 200 Montevideo units. Cesarean delivery was not performed for labor arrest until at least 4 hours of a sustained uterine contraction pattern of greater than 200 Montevideo units, or a minimum of 6 hours of oxytocin augmentation if this contraction pattern could not be achieved. RESULTS: Five hundred forty-two women were managed by the protocol, and 92% delivered vaginally. The subsequent vaginal delivery rate for parous women who had not progressed (1 cm of cervical dilation or less) despite 2 hours of oxytocin augmentation was 91%, and it was 74% for nulliparas. With no labor progress after 4 hours of oxytocin augmentation, the subsequent vaginal delivery rates were 88% for parous women and 56% for nulliparas. There were no severe maternal complications. One neonate had persistent fetal circulation and one had a positive blood culture, but both did well. CONCLUSION: Extending the minimum period of oxytocin augmentation for active-phase labor arrest from 2 to at least 4 hours was effective and safe.

Female↗
PubMed1999

Station at onset of active labor in nulliparous patients and risk of cesarean delivery.

OBJECTIVE: To determine whether term nulliparas with an unengaged vertex presentation at onset of active labor have a higher risk for cesarean delivery. METHODS: A retrospective cohort of 1250 randomly chosen nulliparous patients at 37-42 weeks' gestation who delivered between 1988 and 1989 were selected. Four hundred forty-seven patients were excluded because of nonvertex presentation, cesarean delivery before active phase of labor, multiple gestation, delivery at less than 37 weeks' or greater than 42 weeks' gestation, induction of labor, or missing charts. For the purpose of this study, active labor was defined as regular contractions with cervical dilatation of at least 3 cm. The station at onset of active labor was recorded. Engagement was considered to be at station 0 or below. RESULTS: Of the 803 patients in the study group, 567 presented unengaged and 236 patients presented engaged. The cesarean rates differed significantly between the two groups: 14% of those unengaged compared with 5% of those engaged (chi2 = 11.9, P < .001). After adjusting for confounding variables, engagement at the time of onset of active labor was associated with lower risk of cesarean delivery (odds ratio .512, 95% confidence interval .285, .922). CONCLUSION: Eighty-six percent of nulliparas with an unengaged vertex at onset of active labor delivered vaginally. Engaged vertex at the onset of active labor was associated with a lower risk of cesarean delivery.

Cesarean Section↗
PubMed1999

Preterm labor: placental pathology and clinical correlation.

OBJECTIVE: To determine the relevance of ischemia in the incidence of preterm labor. A second objective was to document perinatal outcomes for patients with preterm labor classified according to its clinical, functional, and pathologic characteristics (infectious, ischemic, mixed, or idiopathic). METHODS: Perinatal outcomes were evaluated for 145 consecutive patients with preterm labor, subdivided into etiologic categories according to clinical, functional (Doppler), and morphologic (placental pathology) characteristics. A group of 44 normal pregnancies delivered at term served as controls. RESULTS: Of the preterm labor group, 28.3% were classified as ischemic, compared with 4.5% of the control group (odds ratio and 95% confidence interval = 8.28 [1.8, 51.8]; P < .05). Compared with the control group, the preterm labor patients who delivered preterm had higher rates of ischemia (31.4% compared with 4.5%; P < .05) and infection (16.1% compared with 2.3%; P < .05). Among the preterm labor group, patients classified in the infectious or ischemic subgroups had a higher rate of preterm delivery (95.0% and 90.2% compared with 73.2%; P < .05), admission to the neonatal intensive care unit (75.0% and 61.0% compared with 40.0%; P < .05), and newborn weight under 1500 g (35.0% and 19.5% compared with 3.7%; P < .05) than the idiopathic subgroup. CONCLUSION: Preterm labor resulting from infection or ischemia is associated with a higher perinatal complication rate than idiopathic preterm labor.

Adult↗
PubMed1999

Risk of cesarean delivery with elective induction of labor at term in nulliparous women.

OBJECTIVE: To quantify the risk of cesarean delivery associated with elective induction of labor in nulliparous women at term. METHODS: We performed a cohort study on a major urban obstetric service that serves predominantly private obstetric practices. All term, nulliparous women with vertex, singleton gestations who labored during an 8-month period (n = 1561) were divided into three groups: spontaneous labor, elective induction, and medical induction. The risk of cesarean delivery in the induction groups was determined using stepwise logistic regression to control for potential confounding factors. RESULTS: Women experiencing spontaneous labor had a 7.8% cesarean delivery rate, whereas women undergoing elective labor induction had a 17.5% cesarean delivery rate (adjusted odds ratio [OR] 1.89; 95% confidence interval [CI] 1.12, 3.18) and women undergoing medically indicated labor induction had a 17.7% cesarean delivery rate (OR 1.69; 95% CI 1.13, 2.54). Other variables that remained significant risk factors for cesarean delivery in the model included: epidural placement at less than 4 cm dilatation (OR 4.66; 95% CI 2.25, 9.66), epidural placement after 4 cm dilatation (OR 2.18; 95% CI 1.06, 4.48), chorioamnionitis (OR 4.61; 95% CI 2.89, 7.35), birth weight greater than 4000 g (OR 2.59; 95% CI 1.69, 3.97), maternal body mass index greater than 26 kg/m2 (OR 2.36; 95% CI 1.61, 3.47), Asian race (OR 2.35; 95% CI 1.04, 5.34), and magnesium sulfate use (OR 2.18; 95% CI 1.04, 4.55). CONCLUSION: Elective induction of labor is associated with a significantly increased risk of cesarean delivery in nulliparous women. Avoiding labor induction in settings of unproved benefit may aid efforts to reduce the primary cesarean delivery rate.

Adolescent↗
PubMed1997

Pre-term labor: an intra-uterine inflammatory response syndrome?

Emerging concepts of sepsis suggest that the host response to an infectious stimulus results in some cases of uncontrolled release of inflammatory cytokines leading to signs of sepsis. Systemic inflammatory response syndrome (SIRS) has been suggested as a diagnosis when no etiologic organism can be found. Infection may account for up to 30% of cases of pre-term labor, and may either be clinically-evident or sub-clinical. Inflammatory cytokines can be detected in elevated concentrations in the amniotic fluid and plasma of women with pre-term labor, and human gestational tissues are potentially rich sources of inflammatory cytokines, as found in in vivo and in vitro studies. Also, maternal decidua and fetal membranes produce mRNA for inflammatory cytokines in the setting of infection-associated pre-term labor and normal term labor. Notably, anti-inflammatory cytokines, such as interleukin-10 (IL-10) do not appear to be present in substantial quantities in these pathophysiologic and physiologic conditions. Animal models indicate that pre-term labor can be stimulated by bacteria, bacterial cell wall products, and inflammatory cytokines such as IL-1 and tumor necrosis factor. These findings suggest that: (1) infectious stimuli may result in the liberation of inflammatory cytokines from gestational tissues leading inevitably to pre-term labor and delivery; (2) inhibition of this process may either be overcome or abrogated, and (3) the mechanisms regulating cytokine production in maternal and fetal tissues are disturbed. Thus, pre-term labor associated with sub-clinical infection may result in a dysregulated local inflammatory response, in which the maternal host response causes an 'intra-uterine inflammatory response syndrome' leading to pre-term labor and delivery.

Amniotic Fluid↗
PubMedDate not supplied

Site-specific augmentation of amnion cyclooxygenase-2 and decidua vera phospholipase-A2 expression in labor: possible contribution of mechanical stretch and interleukin-1 to amnion prostaglandin synthesis.

OBJECTIVE: To investigate a possible site-specific augmentation of prostaglandin (PG) synthesis in the fetal membranes during labor. METHODS: We used reverse transcriptase-polymerase chain reaction or Western blot analysis to evaluate the expression of cytosolic phospholipase A2 (cPLA2) and cyclooxygenase-1, -2 (COX-1, -2), in both the upper and lower parts of the amnion, chorion laeve, and decidua vera tissues from term pregnant women before (n = 8) and after labor (n = 24). Prostaglandin E2 (PGE2) secretion from amnion-derived WISH cells was assessed using enzyme-linked immunosorbent assay after stimulation by cyclic mechanical stretching and interleukin-1 (IL-1). RESULTS: The expression of cPLA2 and COX-1 and COX-2 mRNAs was detected in all samples examined. Western blot analysis revealed that COX-2 expression in the upper part of the amnion, chorion laeve, and decidua vera tissues after labor was 4.7-, 4.9-, and 3.7-fold higher than that before labor, respectively (P < .05 for all). The cPLA2 protein expression in the upper part of the amnion and chorion laeve tissues after labor was 14.0- and 8.8-fold higher than that before labor, respectively (P < .05 for both). Moreover, in specimens obtained after labor, the amnion COX-2 expression and the decidua vera cPLA2 expression in the lower part of the fetal membrane was 1.9- and 2.6-fold higher than the respective levels in the upper part (P < .05 for both). In an in vitro study, cyclic mechanical stretching significantly enhanced IL-1-augmented PGE2 secretion from WISH cells. CONCLUSION: In the lower part of the amnion and decidua vera tissues, adjacent to the dilating cervical canal, PG synthesis was upregulated site specifically after labor. Such enhancement of amnion PG synthesis might be regulated at least partly by IL-1 and cyclic distension.

Amnion↗
PubMed2001

Immersion in water in the first stage of labor: a randomized controlled trial.

BACKGROUND: Current forms of analgesia often have significant side effects for women in labor. Bathing in warm water during labor has been reported to increase a woman's comfort level and cause a reduction in painful contractions. The objective of this trial was to compare immersion in warm water during labor with traditional pain management for a range of clinical and psychological outcomes. METHODS: A prospective randomized controlled trial of 274 pregnant women, who were free from medical and obstetric complications and expecting a singleton pregnancy at term, was conducted at the Women's and Children's Hospital, a maternity tertiary referral center in Adelaide, South Australia. Women in labor were randomized to an experimental group who received immersion in a bath or to a nonbath group who received routine care. Pharmacological pain relief was the primary outcome that was measured, and secondary outcomes included maternal and neonatal clinical outcomes, factors relating to maternal and neonatal infectious morbidity, psychological outcomes, and satisfaction with care. RESULTS: The use of pharmacological analgesia was similar for both the experimental and control groups; 85 and 77 percent, respectively, used major analgesia. No statistical differences were observed in the proportion of women requiring induction and augmentation of labor or in rates of perineal trauma, length of labor, mode of delivery, or frequency of cardiotocographic trace abnormalities. Neonatal outcomes (birthweight, Apgar score, nursery care, meconium-stained liquor, cord pH estimations) revealed no statistically significant differences. Infants of bath group women required significantly more resuscitation than routine group women. Routine group women rated their overall experience of childbirth more positively than bath group women. Psychological outcomes, such as satisfaction with care or postnatal distress, were the same for both groups. CONCLUSION: Bathing in labor confers no clear benefits for the laboring woman but may contribute to adverse effects in the neonate.

Analgesia, Obstetrical↗