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PubMed2004

Is hypotonic dysfunctional labor associated with hypophosphatemia?

OBJECTIVE: The purpose of this study was to determine whether hypotonic dysfunctional labor is associated with hypophosphatemia. STUDY DESIGN: We conducted a prospective nested case control study of term women who were in active labor. Serum phosphate samples were drawn at admission with active labor and before delivery. Phosphate concentration was compared between control subjects and women with hypotonic, dysfunctional uterine contractions. RESULTS: Both serum samples were available for 90 women. Hypophosphatemia was documented in 14% of the participants. There was no significant difference in phosphate concentration between the 2 groups either at admission or before delivery. The mean decrease in phosphate concentration between admission and delivery was similar between the 2 cohorts. CONCLUSION: Although transient hypophosphatemia is found commonly in laboring women, hypotonic dysfunctional contractions are not associated with mild hypophosphatemia.

Adult↗
PubMed2005

Are alterations in plasma protease concentrations during labor associated with poor obstetric outcomes?

OBJECTIVE: The purpose of this study was to assess the association between abnormal connective tissue remodeling during labor as reflected by plasma concentrations of extracellular matrix remodeling proteolytic enzymes and adverse obstetric outcomes. STUDY DESIGN: A prospective observational study of 176 nulliparous women who attended the antenatal clinics at the Mercy Hospital for Women (Melbourne, Australia) from 1999 to 2000. RESULTS: Patients with a prolonged second stage (>120 minutes) had a significantly increased plasma concentration of matrix metalloproteinase 9 after delivery compared with control subjects (P<.001); patients in labor who underwent an emergency caesarean delivery had a significantly lower concentration (P<.001). Patients with a prolonged duration of labor (>11 hours) had a significantly lower urokinase plasminogen activator plasma concentration compared with control subjects (P<.01). CONCLUSION: Altered plasma concentrations of extracellular matrix remodeling proteolytic enzymes, matrix metalloproteinase 9, and urokinase plasminogen activator were found to be associated with abnormal labor and delivery outcomes. This finding may provide a useful predictor of abnormal obstetric outcomes.

Adult↗
PubMed2004

Incidence and characteristics of maternal cardiac arrhythmias during labor.

There is an assumption that pregnancy and labor are prone to a higher incidence of maternal cardiac arrhythmias. We assessed the incidence and characteristics of maternal cardiac arrhythmias during labor and compared the findings with corresponding studies of healthy nonpregnant women and pregnant women not in labor. A high incidence of cardiac arrhythmias during labor (93%) was found among 30 healthy pregnant women; however, other than atrial premature beats, the rate was no higher than among nonpregnant women.

Adolescent↗
PubMed2005

Anxiety sensitivity as a predictor of labor pain.

Psychosocial factors have been implicated in the pain experience during childbirth, which can have both short- and long-term consequences on the mother's health and her relationship with her infant. The present study evaluated important demographic, social, and psychological factors as predictors of multiple dimensions of labor pain among 35 mothers during childbirth. The results indicated that anxiety sensitivity (AS), as measured by the Anxiety Sensitivity Index, shared a significant relation with maximum pain during labor as well as sensory and affective components of pain as measured by the McGill Pain Questionnaire. AS predicted both maximum pain during labor and sensory aspects of pain above and beyond demographic and social factors as well as other theoretically important psychological factors (e.g., depression and state anxiety). These data replicate previous research that has demonstrated the significant impact of AS on pain responding in other areas (e.g., chronic pain) and extend knowledge in this literature to demonstrate the important role that AS serves among women and their experience of labor pain. Clinical implications are highlighted and discussed.

Adolescent↗
PubMed2006

Impact of early admission in labor on method of delivery.

OBJECTIVE: The effect of the timing of admission in labor unit on the method of delivery was evaluated in a cohort study. METHOD: Four hundred and sixty six low-risk nulliparous women who were admitted in the labor unit in latent phase (group 1) were compared with 329 parturient women who were admitted in the active phase (group 2) to determine rate of and reasons for cesarean section, cervical dilation at the time of cesarean, and the rate of labor augmentation. RESULT: The number of cesarean deliveries in group 1 was greater than that in the group 2 (301 vs 80, p<0.0001 ). The main reason for cesarean section in group 1 was dystocia, and in 2, fetal distress. The rate of cesarean section in the women who were augmented was greater in group 1 than in group 2 (54% vs 23%, p<0.0001). CONCLUSION: Later admission in labor increases the rate of spontaneous vaginal delivery in low risk nulliparous women.

Adolescent↗
PubMedDate not supplied

The neuromatrix theory of pain: implications for selected nonpharmacologic methods of pain relief for labor.

Women experience the pain of labor differently, with many factors contributing to their overall perception of pain. The neuromatrix theory of pain provides a framework that may explain why selected nonpharmacologic methods of pain relief can be quite effective for the relief of pain for the laboring woman. The concept of a pain "neuromatrix" suggests that perception of pain is simultaneously modulated by multiple influences. The theory was developed by Ronald Melzack and represents an expansion beyond his original "gate theory" of pain, first proposed in 1965 with P. D. Wall. This article reviews several nonpharmacologic methods of pain relief with implications for the practicing clinician. Providing adequate pain relief during labor and birth is an important component of caring for women during labor and birth.

Female↗
PubMed1982

Biochemistry and pharmacology of the myometrium and labor: regulation at the cellular and molecular levels.

This review presents the essentials of cell biology, biochemistry, and pharmacology of the myometrium and labor, especially as they relate to premature labor. The aim is to explore the neuroendocrine and pharmacologic regulation of myometrial muscle cells in the context of cell membrane function and contractile processes. In the first section, smooth muscle protein structure and interactions are described, the central roles of myosin light-chain kinase, calcium, and cyclic adenosine monophosphate (cAMP) are reviewed. Subsequently, events relating to hormone/drug receptor function and implications for pharmacologic applications are discussed. Finally, the processes of information transfer via hormones and drugs are incorporated into a model which explains how the hormones and drugs used in clinical practice may mediate myometrial contractility. The reader is introduced to current concepts of the cellular, molecular, and pharmacologic aspects of labor in order to facilitate the understanding of medical augmentation of labor and tocolytic therapy.

Actins↗
PubMed1982

Trial of labor after previous cesarean section: prognostic indicators of outcome.

A cross-sectional analytic survey of 92 patients permitted to attempt vaginal delivery after previous lower segment cesarean section ("trial of scar") is reported. Variables which may predict mode of delivery were assessed. Fifty patients (54.3%) were delivered vaginally; 42 patients (45.7%) had repeat cesarean sections in labor. There were three cases of scar dehiscence (3.2%). There were no maternal or fetal mortality. When the cervix was less than 3 cm dilated at initial examination in labor, 10 of 37 patients (27%) were delivered vaginally, compared to 38 of 55 patients (69%) who were delivered vaginally when the cervix was greater than 3 cm dilated. Assessment of cervical dilatation on admission in labor proved to be the most significant prognostic factor at the onset of labor, with regard to successful vaginal delivery in a patient with a lower segment cesarean section scar.

Cervix Uteri↗
PubMed1987

The presence or absence of fetal breathing movements as a predictor of outcome in preterm labor.

The presence or absence of fetal breathing movements may be helpful in differentiating between true and false preterm labor. We attempted to demonstrate the clinical utility of this simple ultrasonic observation in predicting short-term delivery outcome during suspected preterm labor. A total of 50 pregnancies between 26 and 34 weeks' gestation with presumed preterm labor were observed in a prospective manner. During 20 minutes of observation with real-time ultrasound at the time of admission, fetal breathing movements were observed in 33 patients and considered absent in the remaining 17 patients. In those pregnancies with absent fetal breathing movements, true labor with subsequent delivery occurred in 16 patients. Of the 33 pregnancies with fetal breathing movements present, 29 continued for greater than 48 hours. It appears that the absence of fetal breathing movement is a reliable indicator of imminent preterm delivery, irrespective of fetal membrane status (p less than 0.0001). The observed mean sensitivity and specificity of this phenomenon in predicting short-term delivery outcome are 96.6% +/- 3.3% (mean +/- SD) and 80.0% +/- 8.9%, respectively. A multivariant statistical model based on the frequency of contractions, white blood cell counts, initial cervical examination results, and premature rupture of membranes could successfully predict delivery outcome in 40% to 75% of cases. The addition of fetal breathing movement analysis to the model allowed for the correct prediction of outcome in 90% of the cases.

Delivery, Obstetric↗
PubMed2002

Induction of labor for vaginal birth after cesarean delivery.

A recent population-based study of vaginal birth after cesarean delivery (VBAC) attempts observed uterine rupture rates of 24.5 per 1,000 with prostaglandin-induced labor, while the uterine rupture rates with spontaneous labor and labor induced without prostaglandins were lower (5.2/1,000 and 7. 7/1,000 respectively). The authors did not confirm the diagnoses by examining individual medical records, so the actual incidence of uterine rupture may have been overstated. Despite this limitation, the Committee on Obstetric Practice concludes that the risk of uterine rupture during VBAC attempts is substantially increased with the use of various prostaglandin cervical ripening agents for the induction of labor, and their use for this purpose is discouraged.

Cesarean Section↗
PubMed1999

Does the station of the fetal head during epidural analgesia affect labor and delivery?

OBJECTIVE: To assess whether the station of the fetal head when lumbar epidural analgesia is administered influences the duration or the mode of delivery in low-risk laboring women. METHODS: We prospectively evaluated 131 consecutive cases of low-risk parturients at term who requested intrapartum epidural analgesia. Obstetric outcome of 65 parturients who underwent epidural analgesia when the fetal head was low in the birth canal was compared to 66 patients whose fetal head station was above the ischial spine. RESULTS: Both groups were similar in their obstetric characteristics. Cervical dilatation when performing the epidural analgesia was similar in both groups. The duration of labor and mode of delivery, as well as percentage of malpositions, were not significantly different in the two groups. CONCLUSIONS: The station of the fetal head while initiating epidural analgesia does not influence the duration of labor or the mode of delivery. Therefore, there is no justification to delay epidural analgesia in labor until the presenting fetal part is engaged.

Adult↗
PubMed2000

Criteria for failed labor induction: prospective evaluation of a standardized protocol.

OBJECTIVE: To assess the safety and efficacy of a protocol that mandated at least 12 hours of oxytocin administration after membrane rupture before cesarean delivery for failed labor induction in the latent phase. METHODS: Gravidas at or beyond 36 weeks' gestation undergoing indicated induction with cervical dilatation up to 2 cm were studied prospectively. Prior cesarean was an exclusion criterion. If the fetal heart rate pattern was reassuring, cesarean was not permitted before the active phase of labor (4-cm dilatation and at least 90% effacement or 5-cm dilatation regardless of effacement) unless the membranes had been ruptured and oxytocin administered for at least 12 hours. RESULTS: Five hundred nine women were treated according to protocol; 360 (71%) were nulliparas and 149 (29%) were parous. Twenty-five percent of nulliparas and 9% of parous women were delivered by cesarean. After 6 hours of ruptured membranes and oxytocin, 14% of nulliparas were still in the latent phase; 39% of whom delivered vaginally, compared with 7% still in the latent phase after 9 hours (vaginal delivery rate 28%), and 4% after 12 hours (vaginal delivery rate 13%). In contrast, after 6 hours of ruptured membranes and oxytocin, only five (3%) parous women were still in the latent phase. Among those, none remained in the latent phase for 12 hours and all were delivered vaginally. No women had serious complications. Severe neonatal morbidities were infrequent and not related to duration of the latent phase. CONCLUSION: By requiring a minimum of 12 hours of oxytocin after membrane rupture before failed labor induction could be diagnosed, many nulliparas who remained in the latent phase at 6 and 9 hours had safe vaginal deliveries, and failed labor induction was eliminated as an indication for cesarean in parous women.

Adult↗
PubMed1999

Active management of labor.

The active management of labor may be one approach to achieving lower rates of intervention. Numerous institutions have reported lower CS rates since initiating this labor management scheme, and concurrent decreases in the length of labor and infectious morbidity have been demonstrated. Sufficient data now exist to conclude that such programs can be instituted without deleterious effects on neonatal outcomes. Nevertheless, success in decreasing CS rates has not been uniform and may be confined to certain settings. Other approaches to labor management may be as good or better at achieving low rates of intervention with minimum morbidity. Any approach that emphasizes advocacy for vaginal birth is likely to produce some success and should receive support.

Cesarean Section↗
PubMedDate not supplied

Comparative evaluation of four different infusion rates of ropivacaine (2 mg/mL) for epidural labor analgesia.

BACKGROUND AND OBJECTIVES: Previous studies have reported comparable efficacy for ropivacaine and bupivacaine when used for labor analgesia at concentrations of 2.5 mg/mL. In this multicenter study, we assessed ropivacaine at the commercially available concentration of 2 mg/mL (0.2%) for labor pain management. METHODS: After Institutional Review Board approval and informed consent, 128 women at term were randomly assigned to receive ropivacaine at one of the four infusion rates via a lumbar epidural catheter. Analgesia was initiated with a 5-mL test dose, followed by injections of 5-15 mL of 2 mg/mL ropivacaine. The continuous infusion was then started at 4, 6, 8, or 10 rmL/hour. Rescue analgesia was provided with 5-mL "top-up" injections as necessary to provide maternal comfort. Pain relief was assessed by using a visual analog pain scale (VAPS) and motor block was assessed by using a modified Bromage scale. RESULTS: All infusion regimens effectively decreased VAPS, and most patients in all groups had minimal or no motor block at the end of the first stage of labor. Mean total number of the top-up injections required per patient were 3, 2, 1.5, and 1.4, respectively, in the 4, 6, 8, and 10-mL/hour groups (P < .05, 4 mL/hour vs. all other groups). Despite receiving more total bolus dosages, the 4-mL/hour group had less motor block in the lower extremities (P < .05). Apgar scores and neurological adaptive capacity scores were similar for all groups. CONCLUSIONS: The 2 mg/mL of ropivacaine produces satisfactory labor analgesia at epidural infusion rates of 4, 6, 8, and 10 mL/hour, provided supplemental bolus dosages are available. Clinically, a rate of 6 mL/hour may be the lowest effective rate that provides the best combination of pain relief, motor block, and rebolusing, although rates of 8 and 10 mL/hour produced similar results.

Adult↗
PubMed2002

Intrapartum fetal head position I: comparison between transvaginal digital examination and transabdominal ultrasound assessment during the active stage of labor.

OBJECTIVE: To test the null hypothesis that no correlation exists between transvaginal digital and the gold standard technique of transabdominal suprapubic ultrasound assessments of fetal head position during labor. A secondary objective was to compare the performance of attending physicians vs. senior residents in depicting fetal head position by transvaginal digital examination in comparison with ultrasound, respectively. METHODS: Consecutive patients in active labor at term with normal singleton cephalic-presenting fetuses were included. All participants had ruptured membranes, cervical dilation > or = 4 cm and fetal head at ischial spine station -2 or lower. Transvaginal sterile digital examinations were performed by either senior residents or attending physicians and followed immediately by transverse suprapubic transabdominal ultrasound assessments. Examiners were blinded to each other's findings. Power-analyses dictated number of subjects required. Statistical analyses included Chi-square, Cohen's Kappa test and logistic regression analysis. P < 0.05 was considered statistically significant. RESULTS: One hundred and two patients were studied (n = 102). In only 24% of patients (n = 24), transvaginal digital examinations were consistent with ultrasound assessments (P = 0.002, 95% confidence interval, 16-33). Logistic regression revealed that cervical effacement (P = 0.03) and ischial spine station (P = 0.01) significantly affected the accuracy of transvaginal digital examination. Parity, gestational age, combined spinal epidural anesthesia, cervical dilation, birth weight and examiner experience did not significantly affect accuracy of the examination. The accuracy of the transvaginal digital exams was increased to 47% (n = 48) (95% confidence interval, 37-57) when fetal head position at transvaginal digital examination was recorded as correct if reported within +/- 45 degrees of the ultrasound assessment. The rate of agreement between the two assessment methods for attending physicians vs. residents was 58% vs. 33%, respectively (P = 0.02) with the +/- 45 degrees analysis. CONCLUSIONS: Using ultrasound assessment as the gold standard, our data demonstrate an overall high rate of error (76%) in transvaginal digital determination of fetal head position during active labor, consistent with the null hypothesis. Attending physicians exhibited an almost two-fold higher success rate in depicting correct fetal head position by physical examination vs. residents in the +/- 45 degrees analysis. Intrapartum ultrasound increases the accuracy of fetal head position assessment during active labor and may serve as an educational tool for physicians in training.

Adolescent↗
PubMed2004

Severe cardiotocographic pathology at labor: effect of acute intravenous tocolysis.

The purpose of this study was to evaluate the effect of acute tocolysis on severely pathological cardiotocographic (CTG) readings during the first stage of labor. Seventy-three consecutive parturients with full-term pregnancy were treated by acute tocolysis with a beta-mimetic agent after recognition of severe CTG abnormality in the first stage of labor. The main outcome measures were normalization or persistence of the CTG pattern after tocolysis. Risk factors with regard to CTG effect of tocolysis were also evaluated. In 67% of cases the CTG pattern normalized at a mean of 4 minutes after the beginning of intravenous tocolysis. No characteristic feature of the parturient, labor course, CTG abnormality, or the parameters of uterine contractive activity was found to be a predictive factor with regard to the CTG effect of tocolysis. No adverse effects of tocolytic therapy were found. Tocolysis with a beta-mimetic agent is an effective method to normalize the CTG pattern during the first stage of labor, even in cases without uterine hypertonicity.

Adult↗
PubMed1995

Influence of spontaneous or induced labor on delivering the macrosomic fetus.

Fetal macrosomia is a known intrapartum risk factor for fetal injury and maternal morbidity. The purpose of this study was to review our experience with macrosomic fetuses in nondiabetic pregnancies and compare perinatal outcomes between those whose labor had been spontaneous or induced. Between January 1989 and December 1991, the 186 pregnancies of infants with birthweights greater than 4000 g (4001 to 5131 g) underwent labor that had been induced (46) or spontaneous (140). Cesarean delivery was more common after induced than spontaneous labor (11 [23.9%] vs 14 [10.0%]; P < 0.03) regardless of parity or gestational age. Frequencies of shoulder dystocia, 1-minute Apgar scores less than 7, and abnormal umbilical blood gas determinations were not different between the two groups. We conclude that spontaneous rather than induced labor is associated with a lower chance of cesarean delivery among those fetuses with birthweights 4000 g or more.

Adult↗
PubMed1995

Maternal serum levels of alpha-fetoprotein and fetal fibronectin as markers of labor in the third trimester.

Unexplained elevations of maternal serum alpha-fetoprotein (MSAFP) in the second trimester have been found to be associated with a two- to fourfold increase in the rate of preterm delivery, but the sensitivity is low. Therefore, we reasoned that MSAFP levels in the third trimester could prove to be a more useful biochemical marker to predict labor. The presence of placental and membrane-derived fetal fibronectin (FFN) in cervicovaginal secretions has recently been shown to predict preterm delivery with a sensitivity of 81.7% and specificity of 82.5%. We postulated that damage to membranes and microscopic breakdown of fetomaternal blood barrier during labor might result in release of AFP or FFN into maternal serum. Maternal serum alpha fetoprotein and fetal fibronectin levels were measured prospectively in 29 patients in active labor at term and in 25 controls undergoing elective cesarean section. Neither MSAFP nor serum FFN levels were associated with labor at term. We did, however, note significantly higher MSAFP levels in mothers bearing male fetuses versus female fetuses (p < 0.01). Since the current literature supports a sex difference in the MSAFP levels in the second trimester, this does not appear to change as gestation advances. Further studies are needed to determine if, in addition to maternal weight and race, MSAFP levels should be also adjusted for fetal sex diagnosed on sonography.

Adult↗