Dysfunctional Labor Research Articles

Oxytocin: Its Mechanism of Action and Receptor Signalling in the Myometrium

Oxytocin is a nonapeptide hormone that has a central role in the regulation of parturition and lactation. In this review, we address oxytocin receptor (OTR) signalling and its role in the myometrium during pregnancy and in labour. The OTR belongs to the rhodopsin-type (Class 1) of the G-protein coupled receptor superfamily and is regulated by changes in receptor expression, receptor desensitisation and local changes in oxytocin concentration. Receptor activation triggers a number of signalling events to stimulate contraction, primarily by elevating intracellular calcium (Ca(2+) ). This includes inositol-tris-phosphate-mediated store calcium release, store-operated Ca(2+) entry and voltage-operated Ca(2+) entry. We discuss each mechanism in turn and also discuss Ca(2+) -independent mechanisms such as Ca(2+) sensitisation. Because oxytocin induces contraction in the myometrium, both the activation and the inhibition of its receptor have long been targets in the management of dysfunctional and preterm labours, respectively. We discuss current and novel OTR agonists and antagonists and their use and potential benefit in obstetric practice. In this regard, we highlight three clinical scenarios: dysfunctional labour, postpartum haemorrhage and preterm birth.

Effect of Oral Propranolol on Labor Induction

Effect of Oral Propranolol on Labor Induction

672: The dysfunctional labor study

672: The dysfunctional labor study

The Influence of Maternal Body Mass Index on Myometrial Oxytocin Receptor Expression in Pregnancy

Obese pregnant women have higher rates of dysfunctional labor patterns, need for oxytocin augmentation, labor induction, postdates pregnancy, and cesarean delivery compared to normal weight pregnant women. We tested the hypothesis that myometrial oxytocin receptor (OXTR) gene and protein expression are affected by obesity in pregnancy. Myometrial samples were obtained at the time of cesarean delivery from the upper aspect of the uterine hysterotomy incision and processed for real-time quantitative polymerase chain reaction and Western blot. There were 63 myometrial samples available for analysis. The median body mass index (BMI) at delivery was 31.0 kg/m(2) (interquartile range, 26.0, 40.0 kg/m(2)), and the median gestational age at delivery was 38.0 weeks (interquartile range, 33.0, 39.1 weeks). The OXTR gene expression did not correlate with maternal BMI at delivery by linear regression, and the median OXTR gene expression did not differ between women with a BMI ≤ 30 kg/m(2) and those with a BMI ≥ 40 kg/m(2). The OXTR protein expression was also not affected by maternal BMI. Myometrial OXTR gene expression appears to be independent of BMI at the time of delivery. Dysfunctional labor patterns and increased oxytocin utilization seen in obese women may not be due to differences in OXTR expression, though functional studies are required.

A randomised clinical trial to determine the effect of beta-adrenergic blocking with propranolol on labour

Background. Dysfunctional labour is a common problem, particularly in disadvantaged communities. Women who are anxious during labour have high adrenaline levels, which could lead to dysfunctional uterine contractions through beta-adrenergic receptor stimulation. Objective. To determine whether beta-adrenergic blocking with propranolol would reduce the incidence of dysfunctional labour and decrease the caesarean section rate at Universitas and Pelonomi hospitals, Bloemfontein, South Africa. Study design. A double-blind randomised controlled trial. Methods. Women with prolonged labour during the active phase were randomised into receiving propranolol or a placebo. A standard protocol for managing labour was maintained, including pain relief and oxytocin infusion when necessary. Age, gravidity, parity, maternal weight, blood pressure and pulse rate before and 1 hour after administration of propranolol or placebo, amount of oxytocin given before and after randomisation, time and method of pain relief, time and method of delivery, Apgar score, fetal weight, indication for caesarean section, and any complications experienced were documented. Results. Of the 53 women enrolled in the study, 25 received propranolol and 28 the placebo. There was no statistically significant difference between the two groups in number of caesarean sections performed (p=0.59). The only statistically significant difference was the number of cases in which oxytocin augmentation was used after randomisation. In the propranolol group, only 7 (28.0%) received oxytocin after propranolol was given, while in the placebo group 17 (60.7%) received oxytocin after the placebo was administered (p=0.03). Conclusion. Beta-adrenergic blocking with propranolol did not reduce the caesarean section rate or the duration of labour in our population, but decreased the need for oxytocin.

Women with high BMI: Should they be managed differently due to antagonising action of leptin in labour?

Leptin – a protein hormone is synthesised in the adipose tissue in humans. Its level therefore should be directly proportional to the amount of adipose tissue in the body. There is evidence that leptin may be responsible for various complications in obese and morbidly obese women in labour by its effect on the myometrium causing uterine smooth muscle relaxation (causes less Ca2+ flux in myometrium). By doing this, we believe it opposes oxytocin effect on the myometrium which in fact promotes uterine smooth muscle contractions (causes more Ca2+ flux in myometrium). The opposing action of these two hormone may contribute to the dysfunctional labour process, prolonged first stage of labour, increase in operative vaginal delivery in second stage of labour and increase in caesarean section rate both in first and second stage of labour in obese women. Also, there is increased incidence of postdated pregnancy, induction of labour and atonic postpartum haemorrhage in obese and morbidly obese women. Does this mean labour should be managed differently in women with high BMI?

Spatiotemporal patterning of uterine excitation patterns in human labour

The mechanisms leading to the initiation of normal, premature or dysfunctional human labour are poorly understood, as animal models are inappropriate, and experimental studies are limited. Computational modelling provides a means of linking non-invasive clinical data with the results of in vitro cell and tissue physiology. Nonlinear wave processes – propagation in an excitable medium – provides a quantitatively testable description of mechanisms of premature and full term labour, and a view of changes in uterine electrophysiology during gestation as a trajectory in excitation and intercellular coupling parameter space. Propagation phenomena can account for both premature and full term labour.

¿Es útil la amniotomía de rutina en el trabajo de parto de inicio espontáneo? Una revisión de la literatura

La amniotomía de rutina o sistemática, practicada en gestantes con trabajo de parto de inicio espontáneo, se da en gran parte de hospitales del Perú y el mundo, documentándose su prevalencia hasta en 77%. Sin embargo, poco se conoce acerca de los beneficios y daños que puede ocasionar en el feto y en la madre. Se realizó una búsqueda de la literatura médica, con la finalidad de encontrar evidencia científica sólida que respalde o rechace esta práctica. Se llega a la conclusión que la amniotomía practicada sistemáticamente altera la evolución fisiológica del trabajo de parto, acortándolo hasta en 50 minutos en promedio; sin embargo, este acortamiento no tiene trascendencia clínica ni para el feto ni para la madre. Por el contrario, su práctica de rutina puede aumentar el número de partos disfuncionales y el puntaje Ápgar menor de siete a los cinco minutos.

Decreased myometrial p160 ROCK-1 expression in obese women at term pregnancy

BackgroundObesity is becoming an increasing problem in obstetric practice; it has led to an increase in the risk of caesarean delivery, prolonged pregnancy and dysfunctional labour. It has been postulated that many of these problems are as a result of abnormal myometrial contractility. The RhoA/Rho kinase pathway is involved in calcium sensitisation in the myometrium during labour and contributes to the phosphorylation of myosin phosphatase and thus continued myosin light chain activity, during uterine contractility. The aim of this study therefore, was to investigate the effect of obesity on the expression of various components of the RhoA/ROCK pathway in human myometrium at term pregnancy.MethodsProtein was isolated from myometrial biopsies obtained at elective caesarean section, at term pregnancy from obese women and from those with a normal body mass index. Western blotting was performed using specific primary antibodies to RhoA/ Rho kinase associated proteins.ResultsThe protein expression of p160 ROCK-1 was significantly decreased (P < 0.001) in the myometrium from women in the obese cohort (n = 22) at term pregnancy, compared to women of those of normal body mass index (n = 15). No alteration in expression of the other proteins investigated was noted.ConclusionsThe significant decrease in p160 ROCK-1 protein expression observed in the myometrium of obese women at late gestation may contribute to an inhibitory effect on contractility at labour, due to its contribution to calcium sensitisation and possibly other signalling pathways. These findings are relevant to the concept of compromised myometrial function in obese parturients.

Increased Intravenous Hydration of Nulliparas in Labor

Maternal hydration can affect labor progression and is critical for fetal well-being. When women have restricted oral fluid intake during labor, the rates of dysfunctional labor and cesarean delivery increase. However, studies have reported conflicting results regarding hydration and its effects on labor duration, incidence of labor dystocia, and adverse maternal and neonatal outcomes. Maternal exhaustion and dehydration from prolonged labor have been linked to a more frequent need for epidural analgesia, cesarean delivery, greater occurrence of maternal or fetal infection, adverse birth outcomes, and postpartum hemorrhage. This randomized clinical trial was designed to compare the effects of oral hydration alone with those of oral and intravenous (IV) hydration on duration of labor, need for oxytocin, and incidence of adverse outcomes due to prolonged labor. Eligible patients, aged 18 to 35 years, were nulliparous, with a singleton pregnancy, in spontaneous active labor, with cervical dilation at 4 to 5 cm, gestational age 38 to 40 weeks, normal fetal heart rate tracings, intact membranes, and cephalic presentation. Labor analgesia was not used. Women were randomly assigned to 1 of 4 groups, with control women in group 1 receiving usual care that did not involve an IV infusion of Ringer’s lactate solution. Patients in groups 2, 3, and 4 received an infusion of Ringer’s lactate solution at the respective rates of 60, 120, and 240 mL/h. All participants were allowed to drink water or soft beverages at will. Infusion pumps controlled the flow of Ringer’s lactate solution allotted to the participants in groups 2, 3, and 4. Total fluid volumes were recorded. Main outcome data were duration of the active phase of the first stage of labor, durations of the second and third stages of labor, need for oxytocin, mode of delivery, Apgar scores at 1 and 5 minutes, and volumes of IV and oral fluids. All collected data were analyzed using SPSS. Means were compared using analysis of variance and proportions by the χ2 test. P < 0.05 was considered significant. Of 120 women recruited, 20 had cesarean deliveries, and 100 delivered vaginally. Maternal age and weight, cervical dilation, and station of the fetus were similar in all 4 groups as were neonatal gestational age at birth, birth weight, Apgar scores at 1 and 5 minutes, and presence of meconium in the amniotic fluid. For women who delivered vaginally, the differences in the duration of the active phase of the first stage of labor were significant (252.3 ± 40.9, 237.8 ± 36.4, 231.7 ± 43.5, and 206.2 ± 38.3 minutes for groups 1–4, respectively; P < 0.001). The differences in the duration of the second stage of labor were also significant between groups: 64.3 ± 13.9, 54.8 ± 16.2, 51.3 ± 11.9, and 49.8 ± 11.4 minutes, respectively (P = 0.01). Differences in duration were not significant (P = 0.58) for the third stage of labor. In group 1, 53.3% of patients needed oxytocin augmentation compared with 20.0% in group 4. The percentages of patients who underwent each mode of delivery did not differ significantly. Eight women in group 1 and 2 women in group 4 had a cesarean delivery because of failure to progress or other complications; differences among the 4 groups were not significant. Three newborns in group 1 and 1 neonate in group 3 had an Apgar score less than 7 at 1 minute, but no infants in groups 2 and 4 had scores less than 7. The 4 groups did not differ in volume of oral fluid intake. The incidence of vomiting was 10%, 13.3%, 3.3%, and 6.6% in groups 1 to 4, respectively. Providing adequate hydration during labor is a major concern for obstetric professionals. Infusing Ringer’s lactate solution significantly reduced the mean duration of active labor. A patient’s self-regulated intake of drink and food during labor can help reduce stress and create a feeling of control. Intravenous hydration administered to nulliparous women in active labor significantly reduced labor duration and the frequency of both prolonged labor and oxytocin administration without increasing the occurrence of adverse effects.

Reforming an insider-outsider labor market: the Spanish experience

Abstract This paper presents a case study on reforming a very dysfunctional labor market with a deep insider-outsider divide, namely the Spanish case. We show how a dual market, with permanent and temporary employees, makes real reform much harder, and leads to purely marginal changes that do not alter the fundamental features of labour market institutions. While the Great Recession and the start of the sovereign debt crisis have lately triggered two labor reforms, the political economy equilibrium has not allowed them to be transformational enough. JEL codes H29; J23; J38; J41; J64

‘Ask a Woman’: Childbearing and Ezra's Transformation in 4 Ezra

This article argues that the imagery of childbearing serves as a narrative motif in 4 Ezra. Language of fertility and birth appears regularly in Ezra's theodicy and his quest for knowledge. The angel uses childbearing metaphors to instruct Ezra about the coming transition of the ages: the signs of the end of the old age are dysfunctional birth and labor pains, while the fruitful new age will give birth according to a predetermined schedule. These numerous references to fecundity convey the theme of Ezra's movement toward understanding, leading him toward the pivotal moment when an actual childbearing woman appears before him. By joining in her lament for a precious son, Ezra shares the divine perspective of love, proving himself worthy of receiving esoteric wisdom.

Abnormal labor outcomes as a function of maternal exposure to a catastrophic hurricane event during pregnancy

Hurricane Andrew, which made landfall on August 24, 1992, was one of the most destructive hurricanes in American history, causing atypically high levels of psychological and physical health impairment among the resident population and especially among vulnerable groups. This article investigates whether maternal exposure to Hurricane Andrew during pregnancy increased the risk of dystocia (or dysfunctional labor) and infant delivery by cesarean section, the standard medical response to abnormal labor progression. We analyze 297,996 birth events in Miami-Dade and Broward counties in Florida from 1992 to 1993 using propensity score methodology with stratification and nearest-neighbor matching algorithms. Results show that hurricane-exposed pregnant women were significantly more likely to experience stress-induced abnormal labor and cesarean delivery outcomes as compared to statistically matched comparison groups. The conclusion details the policy implications of our results, with particular attention to the importance of maternal prenatal care in the aftermath of disasters.

Managing obesity in pregnancy

AimsTo identify the proportion of obese women booking for obstetric care. Audit compliance with local and CMACE guidance,1 and assess labour outcomes for these women.BackgroundMaternal obesity is a common obstetric...

A Computational Model of the Ionic Currents, Ca2+ Dynamics and Action Potentials Underlying Contraction of Isolated Uterine Smooth Muscle

Uterine contractions during labor are discretely regulated by rhythmic action potentials (AP) of varying duration and form that serve to determine calcium-dependent force production. We have employed a computational biology approach to develop a fuller understanding of the complexity of excitation-contraction (E-C) coupling of uterine smooth muscle cells (USMC). Our overall aim is to establish a mathematical platform of sufficient biophysical detail to quantitatively describe known uterine E-C coupling parameters and thereby inform future empirical investigations of physiological and pathophysiological mechanisms governing normal and dysfunctional labors. From published and unpublished data we construct mathematical models for fourteen ionic currents of USMCs: currents (L- and T-type), current, an hyperpolarization-activated current, three voltage-gated currents, two -activated current, -activated current, non-specific cation current, - exchanger, - pump and background current. The magnitudes and kinetics of each current system in a spindle shaped single cell with a specified surface area∶volume ratio is described by differential equations, in terms of maximal conductances, electrochemical gradient, voltage-dependent activation/inactivation gating variables and temporal changes in intracellular computed from known fluxes. These quantifications are validated by the reconstruction of the individual experimental ionic currents obtained under voltage-clamp. Phasic contraction is modeled in relation to the time constant of changing . This integrated model is validated by its reconstruction of the different USMC AP configurations (spikes, plateau and bursts of spikes), the change from bursting to plateau type AP produced by estradiol and of simultaneous experimental recordings of spontaneous AP, and phasic force. In summary, our advanced mathematical model provides a powerful tool to investigate the physiological ionic mechanisms underlying the genesis of uterine electrical E-C coupling of labor and parturition. This will furnish the evolution of descriptive and predictive quantitative models of myometrial electrogenesis at the whole cell and tissue levels.

No complacency on severe maternal morbidity and other issues

No complacency on severe maternal morbidity and other issues

651: Fetal blood sampling in normal and dysfunctional labor

651: Fetal blood sampling in normal and dysfunctional labor

Reforming an Insider-Outsider Labor Market: The Spanish Experience

This paper presents a case study on reforming a very dysfunctional labor market with a deep insider-outsider divide, namely the Spanish case. We show how a dual market, with permanent and temporary employees makes real reform much harder, and leads to purely marginal changes that do not alter the fundamental features of labor market institutions. While the Great Recession and the start of the sovereign debt crisis triggered two labor reforms, the political economy equilibrium has not allowed them to be transformational enough.

Canadian Pregnancy Outcomes in Rheumatoid Arthritis and Systemic Lupus Erythematosus

Objective. To describe obstetrical and neonatal outcomes in Canadian women with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE). Methods. An administrative database of hospitalizations for neonatal delivery (1998–2009) from Calgary, Alberta was searched to identify women with RA (38 pregnancies) or SLE (95 pregnancies), and women from the general population matched on maternal age and year of delivery (150 and 375 pregnancies, resp.). Conditional logistic regression was used to calculate odds ratios (OR) for maternal and neonatal outcomes, adjusting for parity. Results. Women with SLE had increased odds for preeclampsia or eclampsia (SLE OR 2.16 (95% CI 1.10–4.21; P = 0.024); RA OR 2.33 (95% CI 0.76–7.14; P = 0.138)). Women with SLE had increased odds for cesarean section after adjustment for dysfunctional labour, instrumentation and previous cesarean section (OR 3.47 (95% CI 1.67–7.22; P < 0.001)). Neonates born to women with SLE had increased odds of prematurity (SLE OR 6.17 (95% CI 3.28–11.58; P < 0.001); RA OR 2.66 (95% CI 0.90–7.84; P = 0.076)) and of SGA (SLE OR 2.54 (95% CI 1.42–4.55; P = 0.002); RA OR 2.18 (95% CI 0.84–5.66; P = 0.108)) after adjusting for maternal hypertension. There was no excess risk of congenital defects in neonates. Conclusions. There is increased obstetrical and neonatal morbidity in Canadian women with RA or SLE.

Reforming an Insider-Outsider Labor Market: The Spanish Experience

This paper presents a case study on reforming a very dysfunctional labor market with a deep insider-outsider divide, namely the Spanish case. We show how a dual market, with permanent and temporary employees makes real reform much harder, and leads to purely marginal changes that do not alter the fundamental features of labor market institutions. While the Great Recession and the start of the sovereign debt crisis triggered two labor reforms, the political economy equilibrium has not allowed them to be transformational enough.