Uterine contractions' pattern in active phase of labor as a predictor of failure to progress

Monitoring uterine contractions during labor: current challenges and future directions

Organ-level models are used to describe how cellular and tissue-level contractions coalesce into clinically observable uterine contractions. More importantly, these models provide a framework for evaluating the many different contraction patterns observed in laboring patients, ideally offering insight into the pitfalls of currently available recording modalities and suggesting new directions for improving recording and interpretation of uterine contractions. Early models proposed wave-like propagation of bioelectrical activity as the sole mechanism for recruiting the myometrium to participate in the contraction and increase contraction strength. However, as these models were tested, the results consistently revealed that sequentially propagating waves do not travel long distances and do not encompass the gravid uterus. To resolve this discrepancy, a model using 2 mechanisms, or a "dual model," for organ-level signaling has been proposed. In the dual model, the myometrium is recruited by action potentials that propagate wave-like as far as 10 cm. At longer distances, the myometrium is recruited by a mechanotransduction mechanism that is triggered by rising intrauterine pressure. In this review, we present the influential models of uterine function, highlighting their main features and inconsistencies, and detail the role of intrauterine pressure in signaling and cervical dilation. Clinical correlations demonstrate the application of organ-level models. The potential to improve the recording and clinical interpretation of uterine contractions when evaluating labor is discussed, with emphasis on uterine electromyography. Finally, 7 questions are posed to help guide future investigations on organ-level signaling mechanisms.

Consistency and timeliness of intrapartum care interventions as predictors of intrapartum stillbirth in public health facilities of Addis Ababa, Ethiopia: a case-control study

Introduction

approximately one-third of the global stillbirth burden occurs during intrapartum period. Intrapartum stillbirths occurring in the health facilities imply that a foetus was alive on admission to labour and had greater chances of survival with optimum obstetric care. Active monitoring and follow-up by skilled birth attendants becomes critical to determine the progress of labour and to decide any emergency obstetrical care actions. Timely monitoring of labour progress indicators including fetal heart rate (FHR), uterine contraction maternal vital signs, vaginal examination (VE) are vital in reducing intrapartum stillbirth.

Methods

a case-control study was conducted using primary data from chart review of medical records of women who experienced intrapartum stillbirth in 20 public health centres and 3 public hospitals of Addis Ababa between July 1^st, 2010 to June 30^th, 2015. Data were collected from charts of all cases of intrapartum stillbirths meeting the inclusion criteria and randomly selected charts of controls from each public health facility in 2: 1 control to case ratio.

Results

over 90% of both cases and controls received FHR monitoring care albeit the timing was substandard. More women in the live birth group than intrapartum stillbirth group received timely care related to uterine contraction (OR 2.42, 95% CI 1.77 - 3.30) and blood pressure monitoring (aOR 1.41, 95% CI 1.09 - 1.81). 1.2% and 0.3% of women in the intrapartum stillbirth and livebirth groups developed eclampsia respectively.

Conclusion

substandard timing and application of labour monitoring interventions including FHR, uterine contraction can predict intrapartum stillbirth in public health facilities.

An Integrated Review of Uterine Activity Monitoring for Evaluating Labor Dystocia

Introduction:

Labor dystocia is the most common cause of cesarean birth in the United States, yet how dystocia develops during labor remains elusive. Uterine activity monitoring has significant potential for advancing our understanding of labor dystocia. While evaluating contraction frequency and amplitude is a common component of labor dystocia management, the literature describing the relationship between measures of uterine activity and labor dystocia is heterogeneous and has not been synthesized to identify the best methods for use in clinical investigation.

Methods:

We conducted a literature search for original research exploring the relationship between uterine activity and labor dystocia published between 2000 and 2019. Included articles were critically reviewed and synthesized.

Results:

Across 11 identified studies, investigators employed 3 different techniques for monitoring uterine activity and 9 different measures were employed. Uterine activity measures, including Montevideo units, uterine electromyography power density spectrum and sample entropy, and the fall-to-rise ratio of contraction shape, detected patterns associated with labor dystocia or cesarean birth.

Discussion:

The use of multiple regression with clinical covariates and a uterine activity measure increased the accuracy of predicting cesarean delivery. Uterine electromyography may be especially useful to evaluate labor dystocia phenotypes to differentiate uterine muscle fatigue from understimulation and lead to algorithms for increased precision in the diagnosis of labor dystocia and innovative approaches to treatment.

The Effect of Epidural Analgesia Alone and in Association With Other Variables on the Risk of Cesarean Section

Introduction:

Epidural analgesia (EA) is the most widespread pharmacologic method of labor pain relief. There remains disagreement, however, regarding its adverse effects. The objective of this study was to determine the effect of EA administration on the risk of cesarean delivery and its causes (e.g., stalled labor, risk of loss of fetal well-being, among others) and the degree to which this effect may be modulated by mother-, newborn-, and labor-related variables.

Method:

A retrospective cohort observational study was conducted including all deliveries in a Spanish public hospital between March 2010 and March 2013 ( N = 2,450; EA = 562, non-EA = 1,888).

Results:

Risk of a cesarean section was significantly increased by EA administration (odds ratio [ OR] = 2.673; p < .0001). The percentage of cesarean deliveries due to the risk of loss of fetal well-being was significantly higher in the EA (47.8%) versus non-EA group (27.5%; OR = 1.739; p = 0.0012,). The EA-associated risk of cesarean section was not significantly modified as a function of maternal age or parity, fetal position, newborn weight, weeks of gestation, or sedation administration alone. However, these variables in combination may increase the risk. We present multivariate models for each group that account for these variables, allowing for estimation of the risk of a cesarean delivery if EA is administered.

Conclusion:

EA is associated with an increased risk of cesarean delivery. Other variables in combination (maternal age or parity, fetal position, newborn weight, weeks of gestation, or sedation administration) may increase this risk.