Clinical application of nitric oxide donors and blockers.
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Animals↗
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Changes in fetal heart rate and uterine patterns associated with uterine rupture.
OBJECTIVE: To determine changes in fetal heart rate (FHR) and uterine patterns preceding complete uterine rupture. STUDY DESIGN: FHR and uterine patterns of 50 women with uterine rupture were compared with 601 tracings of controls without scarred uteri. Tracings were interpreted using the National Institute of Child Health and Human Development Research Planning Workshop guidelines. RESULTS: Interobserver and intraobserver agreements of FHR and uterine tracings in the uterine rupture group were excellent (kappa of .96 for both variables). Comparing tracing patterns during the first stage, higher rates of severe fetal bradycardia (4.0% vs. 1.0%, P = .064), fetal tachycardia (8.0% vs. 2.3%, P = .042), reduced baseline variability (24.0% vs. 12.5%, P = .021), uterine tachysystole (10.0% vs. 0.8%, P < .001) and disappearance of contractions (6.0% vs. 0, P < .001) were noted among patients with uterine rupture as compared to the controls. During the second stage of labor, patients with uterine rupture had significantly higher rates of reduced baseline variability (47.8% vs. 7.7%, P < .001), severe variable decelerations (26.1% vs. 6.4%, P = .004), uterine tachysystole (22.0% vs. 0.5%, P < .001) and disappearance of contractions (13.0% vs. 0, P < .001). Using a backward, stepwise multiple logistic regression model, severe fetal bradycardia (OR = 8.2, 95% CI 2.2-31.0, P = .002) and uterine tachysystole (OR = should alert the 8.0, 95% CI 1.7-37.9, P = .008) were found to be independent patterns preceding uterine rupture during the first stage of labor. Likewise, during the second stage, reduced baseline variability (OR = 4.2, 95% CI 1.4-12.3, P = .009) and uterine tachysystole (OR = 42.3, 95% CI 10.6-168.3, P < .001) were independently associated with uterine rupture in another multivariable analysis. CONCLUSION: Abnormal monitor patterns among women presenting with risk factors for uterine rupture, specifically uterine tachysystole, reduced baseline variability and severe bradycardia, should act as warning signs to the obstetrician.
Adult↗
A second-stage partogram.
OBJECTIVE: To describe a second-stage partogram based on a system of scoring the descent and position of the fetal head and to use this system for studying progress in the second stage of labor and predicting mode of delivery and obstetric outcome. METHODS: A prospective observational study of 1413 women at term with a singleton, cephalic presentation. The position and station of the fetal head were observed and scored at diagnosis of the second stage of labor, 1 hour later, and then at 30 minute intervals until delivery was achieved. The score at diagnosis of the second stage of labor was assessed for its ability to predict eventual mode of delivery and duration of labor. A normogram was defined for nulliparas and multiparas and was used to define normal and abnormal progress in the second stage, associated factors in the first stage of labor, and mode of delivery. RESULTS: Increasing total score at the start of the second stage of labor is associated with increasing chance of spontaneous vaginal delivery (odds ratio [OR] 1.68 for nulliparas, 1.59 for multiparas), decreasing chance of instrumental vaginal delivery (OR 0.67 for nulliparas, 0.64 for multiparas), and emergency cesarean delivery (OR 0.39 for nulliparas). Abnormal progress as defined by the normogram is associated with use of epidural anesthesia, induction of labor, augmentation, dystocia, and increased incidence of operative delivery. No significant difference is found between normal and abnormal second stages of labor in fetal outcome as determined by Apgar scores. CONCLUSION: The second-stage partogram offers an objective basis for management of the second stage of labor.
Delivery, Obstetric↗
Does preterm cervical dilatation imply imminent labor in multifetal pregnancies?
OBJECTIVE: Women with multifetal pregnancies are at increased risk of preterm labor and delivery compared with singleton pregnancies. Presentation with advanced cervical dilatation of 3-4 cm is generally regarded as being in the midst of the first stage of labor. The purpose of this report is to present our experience in cases of advanced cervical dilatation and arrested preterm labor in multifetal pregnancies. METHODS: This study is a retrospective analysis of threatened preterm deliveries in women with multifetal pregnancies. Fifteen cases with advanced cervical dilatation that remained undelivered for at least 10 days are presented and reviewed. RESULTS: Out of 1219 women presenting with multifetal pregnancies to the high-risk maternity unit, 15 women who presented with advanced cervical dilatation of 3-5 cm and remained undelivered for at least 10 days were identified. Eight women presented with twins and seven with triplets. The mean latency period to delivery was 21.7 days (range 10-43 days). The mean gestational age at diagnosis was 31.3 weeks (range 26.3-35.3 weeks). The mean gestational age at delivery was 34.5 weeks (range 29.5-38.0 weeks). Twelve women delivered vaginally in this group, giving a cesarean section rate of 20%. CONCLUSIONS: In the women presented in this series advanced cervical dilatation did not lead directly to preterm labor and delivery, we believe due to their having a multifetal gestation. It is possible that dilatation of the cervix in these cases is not a result of preterm labor but rather a relative cervical incompetence resulting from overdistention of the uterus in twins or higher-order gestations. This phenomenon may be underdiagnosed because of a tendency to forego frequent digital examinations remote from term without a clear indication. More information is therefore needed on the mechanism of cervical change during multifetal pregnancy.
Adult↗
Evaluation of non-reassuring fetal heart rate patterns with fetal pulse oximetry combined with vibratory acoustic stimulation.
OBJECTIVE: To determine the value of fetal pulse oximetry and vibratory acoustic stimulation in the presence of non-reassuring fetal heart rate patterns during labor. DESIGN: Prospective study in women monitored by cardiotocography and fetal pulse oximetry during labor. MATERIALS AND METHODS: During a period of 18 months, 907 consecutive parturients in labor were monitored by cardiotocography. Out of these women, 63 were selected on the basis of a non-reassuring fetal heart rate tracing during the first stage of labor. In these cases, fetal pulse oximetry was applied. Vibratory acoustic stimulation was applied in fetuses without spontaneous reactivity in order to evaluate the fetal status. RESULTS: Our cases were classified into three groups, according to the lower fetal oxygen saturation levels, from the time of oximetry application until delivery. Group A consisted of 29 cases where fetal oxygen saturation levels were > or = 41%, group B (20 cases) with fetal oxygen saturation of 31-40% and group C (14 cases) with levels of < 30%. Spontaneous reactivity was observed in 15 fetuses of group A and seven of group B, while no case of reactivity was noted in group C. Vibratory acoustic-induced reactivity was associated with low fetal oxygen saturation levels. The mean umbilical artery pH levels were 7.29 +/- 0.051 in group A, 7.21 +/- 0.057 in group B and 7.04 +/- 0.05 in group C. CONCLUSION: Fetal pulse oximetry should be indicated not only in fetuses without any reactivity but also in those with induced reactivity, after the application of vibratory acoustic stimulation.
Acoustic Stimulation↗
Factors associated with vaginal birth after cesarean in a maternity hospital of Rio de Janeiro.
OBJECTIVES: Identifying characteristics associated with vaginal birth after cesarean. STUDY DESIGN: Case-control study based on medical records. STUDY POPULATION: women with previous cesarean, who had delivered in a public Rio de Janeiro maternity hospital between 1992 and 1996. SAMPLE: 141 cases (vaginal births after cesarean) and 304 controls (a new cesarean after other(s)). Multivariate analysis with logistic regression was carried out. RESULTS: The following characteristics were associated with greater probability of vaginal birth (IC=95%): only one previous cesarean (OR=19.05; IC=6.88-52.76); cervical dilatation at admission above 3 cm (OR=8.86; IC=4.93-15.94); gestational age below 37 weeks (OR=3.01; IC=1.40-6.46); history of at least one previous vaginal birth (OR=2.12; IC=1.18-3.82); level of education below high school (OR=1.94; IC=1.02-3.69). Chronic hypertension reduced the chances of vaginal birth (OR=0.44; IC=0.22-0.88). CONCLUSIONS: Among the factors that can be modified to reduce the number of repeated cesareans are: trial of labor promotion, reducing admission of women at early stages of labor and adequate hypertension management during pregnancy. CONDENSATION: Among the factors that can be modified to reduce the number of repeated cesareans are: the trial of labor promotion for women who present previous cesarean, reducing admission of women at early stages of labor and adequate hypertension management during pregnancy.
Adolescent↗
Nitric oxide as the final metabolic mediator of cervical ripening.
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Animals↗
Spinal clonidine prolongs labor analgesia from spinal sufentanil and bupivacaine.
UNLABELLED: We sought to determine whether spinal clonidine 50 microg prolongs the analgesia from the spinal administration of sufentanil 7.5 microg and bupivacaine 2.5 mg early in the first stage of labor. Thirty patients were randomized to receive a 2-mL spinal injection of sufentanil 7.5 microg + bupivacaine 2.5 mg with or without clonidine 50 microg using a combined spinal-epidural (CSE) technique. Pain, nausea, pruritus, sedation, motor block, blood pressure, and heart rate were assessed until the patient requested additional analgesia. Analgesia was significantly prolonged in patients who received spinal sufentanil + bupivacaine + clonidine (197 +/- 70 vs 132 +/- 39 min; P = 0.004). Pain scores and side effects, including motor block, sedation, and hypotension, were similar between groups. Spinal clonidine significantly prolongs labor analgesia from spinal sufentanil and bupivacaine without producing serious adverse side effects. IMPLICATIONS: We studied the effects of spinal clonidine administered with spinal sufentanil and bupivacaine on labor analgesia using a combined spinal-epidural technique and conclude that spinal clonidine significantly prolongs labor analgesia from spinal sufentanil and bupivacaine without producing serious adverse effects.
Adult↗
Local anesthetic requirements are greater in dystocia than in normal labor.
BACKGROUND: Dystocia is characterized by abnormal progress of labor and is a common contemporary indication for cesarean delivery in the United States. There has been considerable controversy as to whether epidural analgesia causes dysfunctional labor leading to cesarean delivery for dystocia. The minimum local analgesic concentration (MLAC) is a clinical model used to determine the relative potencies of local anesthetics in the first stage of labor. In this article, the authors report a prospective study determining the MLAC of bupivacaine in early labor of parturients who eventually delivered either vaginally or via cesarean section. METHODS: An up-down sequential allocation technique was used to determine the MLAC of bupivacaine in 57 nulliparous parturients assigned to either vaginal delivery or cesarean section arms. In addition, patients were assigned to groups receiving or not receiving intravenous oxytocin at the time of epidural placement. Only patients who delivered by the assigned delivery mode were included in the MLAC analyses. RESULTS: Parturients who later delivered vaginally had 25% and 31% lower MLAC values (0.078% and 0.085% wt/vol bupivacaine, receiving or not receiving intravenous oxytocin, respectively) than those who later delivered by cesarean section (0.102% and 0.106% wt/vol bupivacaine, receiving or not receiving intravenous oxytocin, respectively). CONCLUSIONS: These data suggest that an increased local anesthetic requirement for epidural labor analgesia is associated with more intense pain related to dystocia. Women in early, clinically normal labor but who later develop dystocia require more local anesthetic and, by inference, are experiencing more severe pain than women who deliver vaginally. This association should be considered when studying the relation between the method of labor analgesia and the course of labor.
Adult↗
Early versus late initiation of epidural analgesia in labor: does it increase the risk of cesarean section? A randomized trial.
OBJECTIVE: To determine whether early initiation of epidural analgesia in nulliparous women affects the rate of cesarean sections and other obstetric outcome measures. STUDY DESIGN: A randomized trial in which 449 at term nulliparous women in early labor, at less than 3 cm of cervical dilatation, were assigned to either immediate initiation of epidural analgesia at first request (221 women), or delay of epidural until the cervix dilated to at least 4 cm (228 women). RESULTS: At initiation of the epidural the mean cervical dilatation was 2.4 cm in the early epidural group and 4.6 cm in the late group (P < 0.0001). The rates of cesarean section were not significantly different between the groups--13% and 11% in the early and late groups, respectively (P = 0.77). The mean duration from randomization to full dilatation was significantly shorter in the early compared to the late epidural group--5.9 hours and 6.6 hours respectively (P = 0.04). When questioned after delivery regarding their next labor, the women indicated a preference for early epidural. CONCLUSION: Initiation of epidural analgesia in early labor, following the first request for epidural, did not result in increased cesarean deliveries, instrumental vaginal deliveries, and other adverse effects; furthermore, it was associated with shorter duration of the first stage of labor and was clearly preferred by the women.
Analgesia, Epidural↗
Intrapartum amniotic fluid index and its relationship to fetal distress.
Amniotic fluid index was measured in 50 consecutive laboring women after membrane rupture. The 10th percentile of the normal range was 6.2 cm. Thirty-three women had a repeat measurement by a second observer. Although there was no systematic bias between the two observers, the limits of agreement were wide: 95% of the measurements by one observer were between 0.59 and 2.07 times those of the second. Closer agreement was observed when amniotic fluid index was low (less than 6.2 cm). The relationship between intrapartum amniotic fluid index and fetal distress was then investigated in a further 60 laboring women. When compared with women with a normal intrapartum amniotic fluid index, women with a low amniotic fluid index had higher incidences of fetal heart rate abnormalities during the first stage of labor (64% vs 20%, p less than 0.01), meconium (grade II or III) at delivery (64% vs 35%, p less than 0.05), and operative delivery for fetal distress (57% vs 17%, p less than 0.01). Umbilical artery pH and Apgar scores were, however, similar for the two groups. Measurement of intrapartum amniotic fluid index may be an appropriate method for selecting women suitable for intrapartum aminoinfusion.
Amniotic Fluid↗
Effect of aspirin on bleeding time during elective abortion.
The template bleeding time, indicative of a predictable measure of potential blood loss due to altered platelet function, is unaffected by pregnancy or by the first stage of labor. Two tablets of aspirin (650 mg), but not sodium salicylate or acetaminophen, significantly prolongs the template bleeding time for at least 26 hours after consumption in patients undergoing first or second trimester induced abortion. Patients anticipating induced pregnancy interruption should refrain from any aspirin consumption for at least 26 hours prior to abortion.
Abortion, Induced↗
Raspberry leaf in pregnancy: its safety and efficacy in labor.
OBJECTIVE: Many women consume the raspberry leaf herb during their pregnancies in the belief that it shortens labor and makes labor "easier." METHODOLOGY: Because of the paucity of research regarding this herb, particularly in relation to pregnancy and birth, the authors undertook a double-blind, randomized, placebo-controlled trial. The sample consisted of 192 low-risk, nulliparous women who birthed their babies between May 1999 and February 2000 at a large tertiary-level hospital in Sydney, Australia. The aim of the study was to identify the effect and safety of raspberry leaf tablets (2 x 1.2 g per day), consumed from 32 weeks' gestation until labor, on labor and birth outcomes. RESULTS: Raspberry leaf, consumed in tablet form, was found to cause no adverse effects for mother or baby, but contrary to popular belief, did not shorten the first stage of labor. The only clinically significant findings were a shortening of the second stage of labor (mean difference = 9.59 minutes) and a lower rate of forceps deliveries between the treatment group and the control group (19.3% vs. 30.4%). No significant relationship was found between tablet consumption and birth outcomes. CONCLUSION: The lack of significant differences between the groups on measures expected to demonstrate the effect of raspberry leaf ingestion during pregnancy on labor prompted consideration of the issue of effectiveness of dosage level. Suggestions for further research are offered.
Double-Blind Method↗
Predicting outcomes of trials of labor in women attempting vaginal birth after cesarean delivery: a comparison of multivariate methods with neural networks.
OBJECTIVE: Our aim was to assess the utility and effectiveness of a neural network for predicting the likelihood of success of a trial of labor, relative to standard multivariate predictive models. STUDY DESIGN: We identified 100 failed trials of labor and 300 successful trials of labor in women with a prior cesarean delivery performed at our institution. Information was collected on >70 potential predictors of labor outcomes from the medical records, including demographic, historical, and past obstetric information, as well as information from the index pregnancy. Bivariate analyses comparing women in whom a trial of labor failed with those whose trial succeeded were performed. These initial analyses were used to select variables for inclusion into our muitivariate predictive model. From the same data we trained and tested a neural network, using a back-propagation algorithm. The test characteristics of the multivariate predictive model and the neural network were compared. RESULTS: From the bivariate analysis a history of substance abuse (adjusted odds ratio, 0.27; 95% confidence interval, 0.09-0.80), a successful prior vaginal birth after cesarean delivery (adjusted odds ratio, 0.13; 95% confidence interval, 0.05-0.31), cervical dilatation at admission (adjusted odds ratio, 0.53; 95% confidence interval, 0.31-0.88), and the need for labor augmentation (adjusted odds ratio, 2.15; 95% confidence interval, 1.14-4.06) were ultimately discovered to be important in predicting the likelihood of the success or failure of a trial of labor. With these variables in the predictive model the sensitivity of the derived rule for predicting failure was 77%, the specificity was 65%, and the overall accuracy was 69%. We also built a network using the 4 variables that were included in the final multivariate model. We were unable to achieve the same degree of sensitivity and specificity that we observed with the regression-based predictive model (sensitivity and specificity, 59% and 44%). CONCLUSION: In this study a standard multivariate model was better able to predict outcome in women ttempting a trial of labor.
Adult↗
Prostaglandin F2alpha and E1 in plasma and amniotic fluid during human pregnancy and labor.
In order to elucidate the significance of PGs in human labor, PGE1 and F2alpha in biological fluid during human pregnancy and labor were measured by RIA newly developed. Analytical studies demonstrated that the levels of PGF2alpha in maternal plasma were 3.7 +/- 2.5 ng/ml a few days before parturition, 2.0 +/- 0.9 ng/ml in the first stage of labor and 1.9 +/- 1.4 ng/ml at delivery. Thus the concentrations of PGF2alpha in maternal plasma showed no significant changes around parturition. On the otherhand, the level of PGF2alpha in amniotic fluid represented a significant increase up to 44.27 +/- 32.81 ng/ml at delivery from 1.45 +/- 0.76 ng/ml before labor at 38-40 weeks of pregnancy (p less than 0.05), although it was uncertain whether this elevation was the cause or effect of uterine contraction. The concentration of PGE1 ranged from 2 to 14 ng/ml around parturition. This indicates that there was little remarkable difference between the levels of PGE1 in plasma and amniotic fluid during the last month of pregnancy and labor. Possible involvement of prostaglandins (PGs) in human labor has been discussed.
Amniotic Fluid↗
Analgesia and anesthesia during labor in Japan and developed countries.
Analgesia and anesthesia during labor were surveyed by the use of a questionnaire sent to university hospitals in USA, UK, France, FRG, GDR, Japan, and also other types of institutions in Japan. A rather negative attitude toward analgesia and anesthesia during labor was encountered less often in Japan than in USA, UK, and FRG, but the actual frequency of use was much less in Japan. Narcotics and/or tranquilizers were most frequently used in the first stage of labor. The only exception was France where lumbar epidural anesthesia was actually used as a method of choice at 70% of the institutions. Lumbar epidural anesthesia or some other regional block was the method of choice in the second stage except in UK where inhalation of nitrous oxide was the method of choice at 48% of the institutions. Augmentation of labor was much more frequent and the number of annual deliveries were much less in Japan. Higher C-section rate was seen in USA.
Analgesia↗
[Paravertebral block for labor analgesia in a parturient with idiopathic thrombocytopenia].
A parturient with idiopathic thrombocytopenia received labor analgesia with bilateral paravertebral blocks, because epidural analgesia was contraindicated due to her low platelet count (69,000.microliter-1) even after intravenous administration of freeze-dried sulfonated human normal globulin (400 mg.kg-1.day-1) and transfusion of platelet (20 units.day-1). In spite of predonisolone (1 mg.kg-1.day-1) p.o., her platelet counts could not increase at early gestation period. Prior to the induction of the labor, two catheters were inserted into T 11 bilateral paravertebral spaces, then 0.2% ropivacaine 10 ml was administered in each side, followed by the infusion at 5 ml.hr-1 each for the management of first stage of labor pain. Labor was induced with oxytocin infusion at 2.5-5.0 mU.min-1. As she requested additional analgesia in the second stage of labor, fentanyl 50 micrograms was administered twice intravenously. The labor course was uneventful with adequate analgesia, and the neonate (2,826 g) was vigorous with Apgar scores 9/10. Complications associated with this block such as hypotension, vascular or pleural punctures and pneumothorax were not seen. Bilateral paravertebral blocks may provide adequate analgesia as an alternative method for labor analgesia in a parturient with thrombocytopenia when conventional epidural analgesia is contraindicated.
Adult↗