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PubMed1996

Immunolocalization of eicosanoid enzymes and growth factors in human myometrium and fetoplacental tissues in failed labor inductions.

OBJECTIVE: To investigate the correlation between myometrial-derived eicosanoids and growth factors during the onset of parturition. METHODS: Myometrial samples were obtained from patients who were delivered by cesarean for failed induction or abnormal fetal heart rate tracings but who experienced normal labor progression until the occurrence of the abnormal tracing. Placentas and fetal membranes were obtained from patients with normal labor, no labor, and failed labor progression. The tissues were processed and sections were immunostained for cyclooxygenases, prostacyclin synthetase (PGI2-S), thromboxane A2 synthetase (TXA2-S), 5-lipoxygenase, epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha), and EGF receptor, using specific antibodies directed against these molecules. RESULTS: Myometrial and fetoplacental tissues from women with normal labor, no labor, and failed labor contain immunoreactive cyclooxygenases, 5-lipoxygenase, TXA2-S, PGI2-S, EGF, TGF-alpha, and EGF receptor. However, their immunostaining intensity, with the exception of EGF receptor, decreased substantially in myometrium from women with failed labor induction compared with those having normal labor progression. No difference was noted in the immunostaining intensity of growth factors and eicosanoid enzymes in the fetoplacental membranes from these patients, except for cyclooxygenases, which were prominent in fetal membranes from normal labor compared with failed labor and no labor. CONCLUSION: Myometrial-derived eicosanoids and growth factors may be important in processes of parturition because reduction in their production in the myometrium is correlated with failed labor induction. Because of the regulatory action of growth factors in eicosanoid biosynthesis in uterine and fetoplacental tissues, EGF/TGF-alpha may indirectly influence the process of parturition by regulating eicosanoid production in the myometrium.

Eicosanoids↗
PubMed2000

Economic burden of hospitalizations for preterm labor in the United States.

OBJECTIVE: To determine patient factors associated with hospital care costs for preterm labor and to develop a clinically applicable cost model for evaluating economic consequences of interventions to reduce preterm-labor hospitalizations. METHODS: Maryland state hospital discharge data from 1993-1996 were used to identify hospitalizations for preterm labor without delivery and preterm labor with early delivery. Median regression was used to determine the association between patient factors and hospital care costs in Maryland and to develop a model to estimate hospital care costs nationally. National estimates of hospitalizations for preterm labor were from the 1994 National Hospital Discharge Survey. RESULTS: During the 4-year study period, there were 25,104 hospitalizations for preterm labor, undelivered, and preterm labor with early delivery in Maryland. Maternal comorbidity, antenatal procedures, types of insurance, and lengths of stay associated significantly with hospital costs for preterm labor. National costs for preterm labor, undelivered, were more than $360 million. Incremental costs for preterm labor with early delivery, compared with term delivery, ranged from $21 million to $191 million. Total expenditures for preterm-labor hospitalization for the United States were estimated in excess of $820 million. CONCLUSION: Hospitalizations for preterm labor comprise a substantial portion of maternal cost of perinatal care in the United States. Maternal comorbidity and procedures account for major differences in costs per admission. Strategies to reduce hospitalizations for preterm labor should focus on economic and clinical outcomes in evaluating their overall values.

Adult↗
PubMed1996

Elevation of amniotic fluid interleukin-4 concentrations in women with preterm labor and chorioamnionitis.

Preterm labor associated with intrauterine infection is characterized by increased amniotic fluid concentrations of various proinflammatory cytokines, including interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, IL-8, and macrophage inflammatory protein-1alpha (MIP-1alpha). The purpose of this study was to determine if preterm labor in women with clinically evident chorioamnionitis is marked by elevations of the anti-inflammatory cytokine interleukin-4 (IL-4) and the T cell growth factor IL-2. Amniotic fluid samples were obtained from (1) women at term, not in labor (n = 10); (2) women at term, in labor (n = 10); (3) women with preterm contractions but undelivered within 1 week of amniotic fluid collection (n = 10); (4) women with preterm labor and delivery without clinically evident chorioamnionitis (n = 10); (5) women with preterm labor associated with chorioamnionitis (n = 8); and (6) women with preterm labor and delivery without infection matched with patients with chorioamnionitis (n = 8). Amniotic fluid concentrations of IL-4 and IL-2 were determined for each sample with a specific and sensitive enzyme-linked immunoassay. We found that women with infection-associated preterm labor and delivery had significantly higher concentrations of IL-4 when compared to appropriately matched controls (p < 0.05). Additionally, women with preterm labor and delivery not associated with infection had higher amniotic fluid IL-4 concentrations than women with preterm contractions but no labor (p < 0.05). Women with term labor had rare modest elevations of amniotic fluid IL-4. No IL-2 was detected in any sample. Our data indicate that amniotic fluid IL-4 is elevated in women with preterm labor and delivery, particularly in association with chorioamnionitis. We suggest that IL-4, although previously considered an anti-inflammatory agent, may have a paradoxical proinflammatory role in the pathogenesis of infection-associated preterm labor.

Adult↗
PubMed1991

Cesarean section before the onset of labor and subsequent motor function in infants with meningomyelocele diagnosed antenatally.

Background. Meningomyelocele can now be detected before birth. Few data are available on its natural history, however, and optimal management at the time of delivery is controversial, although it has been suggested that labor and vaginal delivery may cause pressure on exposed nerve roots, resulting in additional loss of neural function. Methods. To assess the effect of labor and the type of delivery on the level of motor function in fetuses with uncomplicated meningomyelocele, we identified 200 cases of this disorder, accounting for 95 percent of the cases that occurred in the state of Washington during our 10-year study period. We compared the outcomes of 47 infants delivered by cesarean section before labor began, 35 delivered by cesarean section after a period of labor, and 78 who were delivered vaginally (another 40 were ineligible for the study). In cases of meningomyelocele detected prenatally, cesarean section was performed before the onset of labor if isolated meningomyelocele without severe hydrocephalus was present. The infants delivered in this manner were compared with those who were delivered either vaginally or by cesarean section after labor began. Results. At two years of age, the infants who had been exposed to labor were 2.2 times more likely to have severe paralysis than those delivered by cesarean section without labor (95 percent confidence interval, 1.7 to 2.8). Infants delivered by cesarean section before the beginning of labor had a mean (+/- SD) level of paralysis 3.3 +/- 3.0 segments below the anatomical level of the spinal lesion at two years of age, as compared with 1.1 +/- 2.3 for infants delivered vaginally and 0.9 +/- 4.1 for infants delivered by cesarean section after the beginning of labor (P less than 0.001 for both comparisons). Exposure to labor did not affect the frequency of neonatal complications or later intellectual performance. Conclusions. For the fetus with uncomplicated meningomyelocele, delivery by cesarean section before the onset of labor may result in better subsequent motor function than vaginal delivery or delivery by cesarean section after a period of labor.

Cesarean Section↗
PubMed2005

Influence of fixed and time-dependent factors on duration of normal first stage labor.

BACKGROUND: No accurate method, clinical or otherwise, currently exists to determine the onset of labor precisely. The objective of this study was to investigate what influences the duration of first stage labor in women with spontaneous labor and childbirth in a nonclinical setting. METHODS: From a population-based cohort of 1,448 planned home and birth center births, we selected 932 births for absence of pathology, absence of intervention, and completeness of data. Duration of first stage labor was analyzed with regression analysis for duration data or time-to-event analysis, using a specialized Transition Data Analysis software. The effects of fixed (age, parity, education, antenatal classes, infant birthweight, first cervical assessment) and time-varying factors (start of midwifery care, spontaneous rupture of membranes) in labor were estimated with piecewise-constant exponential hazard models. RESULTS: Of the characteristics immutable at the onset of labor, only parity had a strong effect on the duration of first stage labor. Cervical dilatation at first assessment and time-varying factors, such as the timing of spontaneous rupture of membranes and midwifery care, each had a strong influence on labor duration; however, the sequence in which they occurred exerted an even stronger influence. First stage labors were much shorter if the membranes ruptured before rather than after the start of care. CONCLUSION: With the exception of parity, events occurring during labor and their timing have a greater influence on the duration of first stage spontaneous labor than elements which are immutable at the onset of labor. Trials of interventions to influence the duration of labor need to consider not only whether the intervention was applied or not, but also when it was applied, if cause-effect relationships are to become properly understood.

Adult↗
PubMed2001

Characterization of topology-, gestation- and labor-related changes of a cassette of myometrial contraction-associated protein mRNA in the pregnant baboon myometrium.

Our objective was to examine the topology-, gestation- and labor-related changes of estrogen receptor (ER)alpha, progesterone receptor (PR), oxytocin receptor (OTR) and thrombospondin-1 (TSP1) mRNA in pregnant baboon myometrium. ER alpha, PR, OTR and TSP1 mRNAs extracted from the lower uterine segment and fundal myometrium of pregnant baboons not in labor between 121 and 180 days of gestational age (n=9) and in established spontaneous labor between 164 and 193 days of gestational age (n=5) were analyzed by Northern blot. There were no topology-, gestation- or labor-related changes of ER alpha and PR mRNA in or between the lower uterine segment or/and the fundus. OTR mRNA was the same in the lower uterine segment and the fundus from baboons not in labor and non-labor fundal, but not lower uterine segment, myometrial OTR mRNA increased with gestation (R(2)=0.81, P<0.05). Fundal OTR mRNA rose significantly compared with the lower uterine segment during spontaneous labor. TSP1 mRNA increased significantly in both the fundus and lower uterine segment during labor. TSP1 mRNA in the lower uterine segment during spontaneous labor was higher than in the fundus during spontaneous labor. In conclusion, fundal and lower uterine segment ER alpha and PR mRNA remained unchanged in late gestation and spontaneous labor. The increased OTR mRNA may serve as a mechanism to increase uterine sensitivity to OT during late gestation. The higher fundal OTR mRNA compared with the lower uterine segment provides polarity which assists fetal expulsion by uterine contractions during labor. The significance of increased TSP1 mRNA during labor may relate to homeostasis and merits further study.

Animals↗
PubMed2004

Urinary nitric oxide metabolite changes in spontaneous and induced onset active labor.

BACKGROUND: The aim of this prospective, randomized study was to investigate the changes in urinary nitric oxide (NO) metabolite between the latent and the active phases of spontaneous and either prostaglandin E(1) (PGE(1)) or prostaglandin E(2) (PGE(2))-induced labors. METHODS: Eighty-eight singleton pregnant women at 36-41(+) weeks' gestation without signs of fetal distress were enrolled. The first group consisted of 29 pregnant women in whom labor was induced by PGE(1) applied intravaginally. The second group consisted of 29 pregnant women with labor induced by PGE(2) applied intracervically. The third group consisted of 30 women, who had spontaneous active labor. Clinical data of the three groups were assessed as labor progressed. RESULTS: Urinary nitric oxide/creatinine (U NO/Cr) decreased significantly after the onset of active labor in all three groups (p < 0.005), with the percentage decline of 42.2%, 28.6% and 10.1%, respectively. The magnitude of the difference in decline in U NO/Cr after active labor between the PGE(1)-induced and the spontaneous labor group was significantly reduced (p = 0.0047) after adjustment for potential confounders using the generalized estimating equations test (GEE). The duration of the latent phase was significantly shortened in the PGE(1)-induced group as compared with the spontaneous labor group (p < 0.01). CONCLUSIONS: Decreased U NO/Cr may facilitate transition from the latent to the active phase either in spontaneous or induced labors. Our results indicate that U NO/Cr can serve as an easily obtained marker for use in controlling myometrial contractility and cervical ripening at the onset of active labor. The nitric oxide system is present in the human uterus and may contribute to uterine quiescence during pregnancy and show down-regulation in U NO/Cr at the initiation of active labor.

Administration, Intravaginal↗
PubMed2006

[The individual's status in the labor market and health inequity in Brazil].

OBJECTIVE: To investigate inequalities in personal health conditions and in the utilization of healthcare services according in relation to the individual's status in the labor market. METHODS: This study was based on 39,925 males aged 15 to 64 years living in 10 Brazilian metropolitan regions, who took part in the 1998 National Household Survey. They were classified as formal labor, informal labor, unemployed or outside of the labor market. Each category was compared with formal labor regarding sociodemographic characteristics, health status indicators and healthcare utilization. This analysis was by means of Pearson's Chi-square test. Multinomial logistic regression was used to investigate independent associations between labor market status, health status indicators and healthcare utilization. RESULTS: The classification of the participants' status was that 52.2% were formal labor, 27.7% informal labor, 10% unemployed and 10.2% were outside of the labor market. There were significant differences between these categories with respect to age, schooling, household income, household status and region of residence. Independent of the sociodemographic characteristics, unemployment, informal labor status and, especially, exclusion from the labor market remained associated with poor health status. CONCLUSIONS: The individual's status in the labor market is expressed through a gradient of inequality in health conditions. These findings reinforce the need to also consider the individual's status in the labor market in studies on healthcare inequalities.

Adolescent↗
PubMed1995

Management of term breech presentation: a protocol of external cephalic version and selective trial of labor.

OBJECTIVE: The results of a program of external version and selective trial of labor for term breech presentation are reviewed. This is a follow-up to our 1987 report describing management of singleton, term breech presentations and expands our 16-year experience to 1180 cases. STUDY DESIGN: All term breech presentations cared for in 1985 through 1992 are reviewed and outcome contrasted with those predicted in our earlier report. During these 8 years a trial of external version was offered if a breech presentation was identified after 36 completed weeks' gestation and before active labor. The criteria for allowing a trial of labor are detailed. RESULTS: Four hundred sixty-four breech presentations were identified for review. Three hundred eighty-two (82%) were diagnosed before active labor. Of these, 344 (90%) underwent an attempt at external version, of which 174 (51%) were successful. The 290 breech presentations where version either was not attempted or was unsuccessful were stratified into three groups: cesarean section without labor (147), trial of labor with cesarean section (90), and trial of labor with vaginal delivery (53). The 174 cases where version was successful were stratified into two additional groups on the basis of the eventual route of delivery. Careful review of maternal and fetal variables indicates that a trial of labor in selected patients resulted in vaginal delivery in only 37% but was achieved without an increase in fetal or maternal mortality or morbidity. Surprisingly, 54 of the 174 cases where version was successful were ultimately delivered by cesarean section. This 31% rate of cesarean delivery is significantly higher than the 15% rate observed for all cases of term, singleton vertex presentation. A higher prevalence of cases complicated by failed progress in labor and failed induction contributed to the excess. CONCLUSION: External version is successful in 51% of cases of term breech presentation. With careful selection, cases where version has failed can be allowed to labor and be delivered vaginally. The incidence of cesarean section (31%) for those cases where version had been successful was surprisingly high, largely because of an increase in labor abnormalities and failed labor inductions.

Breech Presentation↗
PubMed2001

The relationship between cervical dilatation, interleukin-6 and interleukin-8 during term labor.

BACKGROUND: To determine interleukin-6 and interleukin-8 levels in amniotic fluid, retroplacental blood and maternal serum and relate these values with cervical dilatation in term labor. METHODS: Prospective study. n=78 healthy women undergoing term cesarean section, divided into four groups: controls, n=42, (elective cesarean section; no contractions, membrane rupture or cervical dilatation); latent labor, n=12, (latent phase labor; cervix <2 cm dilated); established labor, n=12, (active labor, cervix 2-5 cm); advanced labor, n=12, (active labor, cervix >5 cm). Interleukin-6 and interleukin-8 were determined by ELISA (pg/ml), placenta and placental bed biopsy examined histopathologically, and amniotic fluid also microbiologically. Results were expressed as median and ranges or mean and standard deviations, as appropriate. For statistical analysis, Mann-Whitney U-tests or Kruskal-Wallis tests were used as applicable (Statview 4.5). Power and linear regression analyses were performed. p<0.05 was considered significant, p<0.001 highly significant. RESULTS: Compared with controls, IL-6 and IL-8 increased significantly with cervical dilatation in all compartments tested for almost all labor groups (p<0.05 to p<0.0001). Significant changes were also seen between latent and advanced labor groups in some compartments (p<0.05), but not between established and advanced labor groups. Intrauterine infection was excluded in any of the patients clinically and on histopathological or microbiological analysis of placentae and amniotic fluid. CONCLUSIONS: In term labor without intraamniotic infection, interleukin-6 and interleukin-8 at the fetomaternal interface and in maternal serum rise significantly with cervical dilatation. These cytokines could be used as markers of active labor if vaginal examination is not applicable.

Adolescent↗
PubMed2006

Trial of labor or repeat cesarean delivery in women with morbid obesity and previous cesarean delivery.

OBJECTIVE: Assess effects of body mass index (BMI) on trial of labor after previous cesarean delivery and determine whether morbidly obese women have greater maternal and perinatal morbidity with trial of labor compared with elective repeat cesarean delivery. METHODS: Secondary analysis from a prospective observational study included all term singletons undergoing trial of labor after previous cesarean delivery. Body mass index groups were as follows: normal 18.5-24.9, overweight 25.0-29.9, obese 30.0-39.9, morbidly obese 40.0 kg/m2 or greater, and were compared for failure and maternal and neonatal morbidities. The morbidly obese trial of labor and elective repeat cesarean delivery were compared for maternal and neonatal morbidities. Multivariable logistic regression analysis controlled for confounding variables. RESULTS: There were 14,142 trial of labor participants and 14,304 elective repeat cesarean delivery participants. Increasing BMI was directly associated with failed trial of labor after previous cesarean delivery: from 15.2% in normal weight (1,344) to 39.3% in morbidly obese (1,638), with combined risk of rupture/dehiscence increasing from 0.9% to 2.1% in morbidly obese women. Among morbidly obese women, trial of labor carried greater than five-fold risk of uterine rupture/dehiscence (2.1% versus 0.4%), almost a two-fold increase in composite maternal morbidity (7.2% versus 3.8%) and five-fold risk of neonatal injury (1.1% versus 0.2%) (fractures, brachial plexus injuries, and lacerations), but no neonatal encephalopathy. Morbidly obese women failing a trial of labor had six-fold greater composite maternal morbidity than those undergoing a successful trial of labor (14.2% versus 2.6%). CONCLUSION: Body mass index correlates with outcomes in trial of labor after previous cesarean delivery. Morbidly obese women undergoing a trial of labor were at increased risk for failure. Increased BMI was associated with greater composite morbidity and neonatal injury compared with elective repeat cesarean delivery, but absolute morbidities were small. Increased risks should be considered before trial of labor after previous cesarean delivery. LEVEL OF EVIDENCE: II-2.

Adult↗
PubMed1977

[Programmed labor: methods, results, guidelines (author's transl)].

The programming of labor (setting the best possbile time under optimal conditions) was carried out in the University Women's Hospital, Freiburg i. Br. between 1970 and 1975 in 1121 cases. No perinatal mortality was reported. The secondary frequency of cesarean section for this primarily uncomplicated labor was 3.21% (general hospital statistics for this time period: 6.29%). The most important factors for the strict standardized method of induction is the observation of the pelvic score (desired: greater than 6) and a moderate dose of oxytocin or prostaglandin based on the essential amniotomy. In a statistical comparison of three groups of patients (n = 786): programmed labor (n = 427), induction via the same type of method where transference was suspected (n = 158), and uncomplicated spontaneous labor (n=183), the results with induced labor were better than those with spontaneous labor. In addition for the fact that the course of labor could be preplanned and the period of labor shortened intrauterine and partal complications occurred less frequently with programmed labor than with spontaneous labor. Placental complications and the tendency toward postpartum atony must be discussed. Minor complications decreased as the weight, length and gestation period of the newborn increased. Individual palpation until the physiological maturity for birth is reached would, therefore, seem to be required. Observe the conditions and increase antepartal controls. Only by setting the exact time for labor with modern methods of supervision is it theoretically possible to eliminate the danger of active management. The organizational problem involved with a general programming of labor poses the major problem at present.

Cesarean Section↗
PubMed2001

Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment.

OBJECTIVE: More than 50% of pregnant women in the United States are using epidural analgesia for labor pain. However, whether epidural analgesia prolongs labor and increases the risk of cesarean delivery remains controversial. STUDY DESIGN: We examined this question in a community-based, tertiary military medical center where the rate of continuous epidural analgesia in labor increased from 1% to 84% in a 1-year period while other conditions remained unchanged-a natural experiment. We systematically selected 507 and 581 singleton, nulliparous, term pregnancies with spontaneous onset of labor and vertex presentation from the respective times before and after the times that epidural analgesia was available on request during labor. We compared duration of labor, rate of cesarean delivery, instrumental delivery, and oxytocin use between these two groups. RESULTS: Despite a rapid and dramatic increase in epidural analgesia during labor (from 1% to 84% in 1 year), rates of cesarean delivery overall and for dystocia remained the same (for overall cesarean delivery: adjusted relative risk, 0.8; 95% confidence interval, 0.6-1.2; for dystocia: adjusted relative risk, 1.0; 95% confidence interval, 0.7-1.6). Overall instrumental delivery did not increase (adjusted relative risk, 1.0; 95% confidence interval, 0.8-1.4), nor did the duration of the first stage and the active phase of labor (multivariate analysis; P >.1). However, the second stage of labor was significantly longer by about 25 minutes (P <.001). CONCLUSION: Epidural analgesia during labor does not increase the risk of cesarean delivery, nor does it necessarily increase oxytocin use or instrumental delivery caused by dystocia. The duration of the active phase of labor appears unchanged, but the second stage of labor is likely prolonged. (Am J Obstet Gynecol 2001;185:128-34).

Adult↗
PubMed2002

Identification of matrix metalloproteinase-9 in amniotic fluid and amniochorion in spontaneous labor and after experimental intrauterine infection or interleukin-1 beta infusion in pregnant rhesus monkeys.

OBJECTIVE: The purpose of this study was to examine the roles of intrauterine infection, inflammation, and spontaneous labor on the expression of matrix metalloproteinase-9 in fetal membranes and amniotic fluid of late pregnant rhesus monkeys. STUDY DESIGN: Pregnant rhesus monkeys with timed gestations were chronically catheterized to allow serial sampling of amniotic fluid before and during experimentally induced intrauterine inflammation. Six animals received group B streptococci into the chorionic-decidual space, and 4 animals received intra-amniotic interleukin-1 beta infusions (10 microg). Three additional animals were serially sampled by amniocentesis through late pregnancy until spontaneous term labor. Amniotic fluid samples were examined by zymography for matrix metalloproteinase-9 and -2 and Western immunoblot for matrix metalloproteinase-9 and -2 and tissue inhibitors of metalloproteinase-1 and -2. Fetal membranes were obtained at cesarean delivery during labor (before rupture), formalin fixed, and embedded in paraffin for immunocytochemistry of matrix metalloproteinase-9 and in situ hybridization of matrix metalloproteinase-9 messenger RNA. Tissues from 2 additional animals were collected as age-matched non-labor controls. RESULTS: In amniotic fluid, the 92-kd latent matrix metalloproteinase-9 was detectable in late pregnancy and increased dramatically, followed by the appearance of the 83-kd active form before spontaneous term delivery. Amniotic fluid matrix metalloproteinase-2 levels (both latent and active forms) remained relatively constant throughout pregnancy and in labor. Both bacteria and interleukin-1 beta rapidly increased the signal of latent matrix metalloproteinase-9 without a consistent increase in the active form before the onset of labor. Chorionic-decidual inoculation of group B streptococci was followed by the expression of latent matrix metalloproteinase-9 before the appearance of group B streptococci in amniotic fluid or the onset of labor. Matrix metalloproteinase-2 increased to a new steady-state level or remained unchanged after group B streptococci inoculation or interleukin-1 beta infusion, respectively. Amniotic fluid tissue inhibitors of metalloproteinase-1 declined and tissue inhibitors of metalloproteinase-2 remained unchanged during early group B streptococci infection, after interleukin-1 beta infusion and on the day of spontaneous term labor. However, both tissue inhibitors of metalloproteinase-1 and -2 levels increased after preterm labor that was induced by group B streptococci. Immunocytochemistry localized matrix metalloproteinase-9 protein to amnion and chorion epithelial and mesenchymal cells and decidual stromal cells. Granular matrix metalloproteinase-9 staining was observed in the connective tissue layer of inflamed fetal membranes. In situ hybridization for messenger RNA confirmed the production of matrix metalloproteinase-9 by amnion and chorion. CONCLUSION: Bacterial- and interleukin-1 beta-induced preterm labor and spontaneous term labor are preceded and accompanied by progressive increases in amniotic fluid matrix metalloproteinase-9 (92 kd) in rhesus monkeys. Amniotic fluid matrix metalloproteinase-9 may serve as a clinical marker for the onset of both preterm and term labor.

Amnion↗
PubMed2003

Changes in the isoforms of the sodium pump in the placenta and myometrium of women in labor.

OBJECTIVE: We determined whether changes in sodium pump isoform abundance accompanied active human labor. STUDY DESIGN: Specimens of placenta, amniochorion, and myometrium were collected from women in active spontaneous labor and from those not in labor. The abundance of the three sodium pump alpha-isoforms was determined by Western blot analysis. RESULTS: Levels of the alpha1 and alpha2 isoforms were comparable in the three tissues for women in labor and not in labor. However, alpha3 isoform abundance in placenta and myometrium (but not amniochorion) was significantly decreased in women in active labor compared with women not in labor (sodium pump alpha3 in placenta: no labor 91.2 +/- 27.6 vs labor 46.9 +/- 3.6 density units, P =.002. Sodium pump alpha3 in myometrium: no labor 52.3 +/- 7.7 vs labor 19.8 +/- 1.6 density units, P =.0002). CONCLUSION: Because reductions in sodium pump number can result in hormone release from secretory tissues and in contraction of muscle, this suggests that the sodium pump may play a significant role in the initiation or maintenance of human labor.

Adult↗
PubMedDate not supplied

Mothers' experiences of labor support: exploration of qualitative research.

OBJECTIVE: To review and synthesize qualitative research studies of women's perceptions of professional labor support. DATA SOURCES: Journal articles dated from 1990 to 2001. Search terms included labor support, labor and delivery, childbirth, birth, and caring during labor. Qualitative studies and combined quantitative/qualitative studies with open-ended questions were included. STUDY SELECTION: The focus of the 17 studies was laboring women's rather than nurses' perceptions of labor support or care during labor. DATA EXTRACTION: Data describing methods, samples, and findings were extracted from study reports. DATA SYNTHESIS: Similarities reported in the study findings were synthesized using a model of labor support. Synthesis of the study findings was reported using exemplary statements in the words of women who experienced labor support. Categories included expectations of labor support, physical comfort, caring and emotional support, interpersonal communication style, communication of information and instructions, advocacy, and competence of the professional. CONCLUSIONS: There were a limited number of qualitative studies of labor support. Professional labor support was influenced by the interpersonal communication style of the caregiver. Cultural differences existed in caregiver actions considered supportive.

Attitude to Health↗
PubMed1996

The expression of cytosolic phospholipase A2 and prostaglandin endoperoxide synthase in ovine maternal uterine and fetal tissues during late gestation and labor.

Gene expression of cytosolic phospholipase A2 (cPLA2) and prostaglandin endoperoxide synthase (PGHS) 1 and 2 was studied in ovine maternal uterine and fetal tissues during glucocorticoid induced premature labor and spontaneous labor and compared with gestational age matched controls not in labor. Northern blot analysis demonstrated that the messenger RNA (mRNA) abundance of cPLA2 and PGHS-2, but not PGHS-1, increased significantly in the endometrium during both glucocorticoid induced premature labor and spontaneous labor. Protein levels of the two enzymes measured by Western blot analyses were also elevated in the endometrium during glucocorticoid induced premature labor. cPLA2 mRNA was detected in the myometrium, but no difference was observed between ewes in labor and their gestational age matched controls not in labor. While the level of PGHS-2 mRNA was below detection in the myometrium with the methods used, the enzyme protein for PGHS-2 in the myometrium was significantly increased in both glucocorticoid induced premature labor and spontaneous labor. Using immunocytochemical methods, PGHS-2 enzyme protein was identified in the endometrial gland epithelial cells and myometrial cells. PGHS-2 mRNA was also detected in the ovine fetal cotyledons in which no differences for PGHS-2 mRNA existed between tissues collected from ewes in labor and ewes not in labor. In contrast, there were no detectable signals for cPLA2 or PGHS-2 mRNA in either amnion or chorion. We conclude that the ovine endometrium and myometrium, but not fetal membranes, are important tissue sites of prostaglandin biosynthesis involved in the process of ovine parturition.

Animals↗
PubMed1999

Differential expression of myometrial oxytocin receptor and prostaglandin H synthase 2, but not estrogen receptor alpha and heat shock protein 90 messenger ribonucleic acid in the gravid horn and nongravid horn in sheep during betamethasone-induced labor.

In the present study, we characterized four myometrial contraction-associated proteins (mCAPs): oxytocin receptor (OTR), prostaglandin H synthase 2 (PGHS2), estrogen receptor alpha (ERalpha), and heat shock protein 90 (Hsp90) messenger RNA (mRNA) expression in the nongravid horn of pregnant sheep and compared them with their expression in the gravid horn that is exposed to a greater degree of stretch. We also examined the regulatory effects of estrogen and progesterone on OTR mRNA expression in ovariectomized nonpregnant sheep. In addition, we determined the ontogeny of mCAP expression in the gravid horn throughout late pregnancy and during spontaneous term labor. Gravid horn and nongravid horn myometria were removed under general anesthesia from control ewes not in labor at 130-140 days gestational age (dGA; n = 3) and during betamethasone-induced labor (n = 6) at the same gestational age. Gravid horn myometrium was also collected from ewes not in labor at 95 dGA (n = 3), 101-110 dGA (n = 3), 111-120 dGA (n = 3), 121-130 dGA (n = 3), 131-140 dGA (n = 3), and 141-145 dGA (n = 4) and from ewes in spontaneous term labor (n = 4). All ewes were carrying single fetuses. Myometrium was also collected from ovariectomized nonpregnant ewes treated with saline (n = 5), estradiol (50 microg/day; n = 5), progesterone (0.3 g, intravaginally; n = 5), and estradiol plus progesterone (n = 5). Myometrial RNA was extracted and analyzed by Northern blot for OTR, PGHS2, ERalpha, and Hsp90 mRNA, normalized for 18S ribosomal RNA or beta-actin. ERalpha, Hsp90, OTR, and PGHS2 mRNA were all significantly up-regulated during betamethasone-induced labor (P < 0.01) in gravid and nongravid horn myometrium. The level of gravid horn OTR mRNA during labor was 3 times the level of nongravid horn OTR mRNA (P < 0.0001). Gravid horn PGHS2 mRNA was also higher than nongravid horn PGHS2 (P < 0.02). In contrast, in spontaneous term labor nongravid horn, ERalpha and Hsp90 mRNA were similar to gravid horn. Myometrial ERalpha and Hsp90 mRNA remained unchanged throughout late pregnancy and increased at spontaneous term labor (P < 0.05). In contrast, myometrial OTR increased around 130 dGA (P < 0.01) and further increased at spontaneous term labor (P < 0.02). Progesterone significantly inhibited myometrial OTR mRNA expression in nonpregnant sheep and estradiol antagonized progesterone's inhibitory effect. Mechanical stretch differentially regulated mCAP mRNA expression in the ovine gravid horn and nongravid horn. Mechanical stretch appears largely responsible for increased OTR mRNA and to a lesser degree PGHS2 mRNA. In addition, endocrine factors may be required for full activation of OTR and PGHS2 mRNA associated with labor. ERalpha and Hsp90 mRNA are not under the control of uterine stretch in keeping with our previous results, indicating that systemic hormones such as estradiol, are prime regulators for these two mCAP mRNA expression during labor.

Animals↗