Placental abruption recorded with real-time electrohysterography : case report

Brief Introduction: A non-invasive technique based on real-time electrohysterography (EHG) is recently developed by our group and being tested at the labour ward (PUREtrace, Nemo Healthcare, Eindhoven, the Netherlands). We present a case of placental abruption and uterine hypertonia recorded with real-time EHG. Materials & Methods: Not applicable. Clinical Cases or Summary Results: A 33-year-old pregnant woman at 35 weeks of gestational age in her second pregnancy presented with vaginal blood loss. Her obstetric history revealed a uterus unicollis bicornis and an intrauterine fetal demise due to placental abruption at 26 weeks of gestational age. In the current pregnancy, prophylactic aspirin 80 mg was described from 12 up to 36 weeks. At admission there were no signs of fetal distress or retroplacental hematoma. The vaginal bleeding stopped, however several days later the pregnancy was complicated by preterm rupture of membranes followed by contractions and two centimetres of dilation. The fetal heart rate tracings showed a normal fetal condition, while monitoring uterine activity using external tocodynamometry was inconclusive. Therefore it was decided to use the EHG, by means of the Nemo Healthcare system consisting of a single abdominal electrode patch (Tocopatch, see Figure 1) and PUREtrace module connected to a Philips Avalon FM30 fetal monitor (Philips, Eindhoven, the Netherlands), which provided a cardiotocogram for real-time interpretation. Only half an hour later the pregnant woman presented acute onset of classical abruption signs such as severe abdominal pain, nausea, vomiting and fetal heart rate abnormality. The electrohysterogram showed a typical pattern of extreme uterine hypertonia (see Figure 2). Maternal vital signs were stable without vaginal blood loss. Within 15 minutes after the event an emergency caesarean delivery was performed, showing total detachment of the placenta. The neonate was born with a heart rate of 30 beats per minute and required neonatal resuscitation: Apgar score 0/6/8, umbilical artery pH 7.00, base deficit 17 mmol/L and neonatal body weight 2560 grams. During admission at the neonatal intensive care unit the newborn infant showed good clinical condition and no neurological sequels. Conclusions: This is the first report of real-time electrohysterography during placental abruption. The EHG showed a very typical pattern. Early recognition of this typical pattern might become important in patients with high risk of placental abruption. (Figure presented)

A mathematical model for simulation of early decelerations in the cardiotocogram during labor

Fetal welfare during labor and delivery is commonly monitored through the cardiotocogram (CTG), the combined registration of uterus contractions and fetal heart rate (FHR). The CTG gives an indication of the main determinant of the acute fetal condition, namely its oxygen state. However, interpretation is complicated by the complex relationship between the two. Mathematical models can be used to assist with the interpretation of the CTG, since they enable quantitative modeling of the cascade of events through which uterine contractions affect fetal oxygenation and FHR. We developed a mathematical model to simulate ‘early decelerations’, i.e. variations in FHR originating from caput compression during uterine contractions, as mediated by cerebral flow reduction, cerebral hypoxia and a vagal nerve response to hypoxia. Simulation results show a realistic response, both for fetal and maternal hemodynamics at term, as for FHR variation during early decelerations. The model is intended to be used as a training tool for gynaecologists. Therefore 6 clinical experts were asked to rate 5 real and 5 model-generated CTG tracings on overall realism and realism of selected aspects. Results show no significant differences between real and computer-generated CTG tracings

Simulation of reflex late decelerations in labor with a mathematical model

Fetal welfare during labor and delivery is commonly monitored through the cardiotocogram (CTG), the combined registration of uterus contractions and fetal heart rate (FHR). From the CTG, the fetal oxygen state is estimated as the main indicator of the fetal condition, but this estimate is difficult to make, due to the complex relation between CTG and oxygen state. Mathematical models can be used to assist in the interpretation of the CTG, since they enable quantitative modeling of the flow of events through which uterine contractions affect fetal oxygenation and FHR. We propose a mathematical model to simulate reflex ‘late decelerations’, i.e. variations in FHR originating from uteroplacental flow reduction during uterine contractions and mediated by the baroreflex and the chemoreflex. Results for the uncompromised fetus show that partial oxygen pressures reduce in relation to the strength and duration of the contraction. Above a certain threshold, hypoxemia will evoke a late deceleration. Results for uteroplacental insufficiency, simulated by reduced uterine blood supply or reduced placental diffusion capacity, demonstrated lower baseline FHR and smaller decelerations during contraction. Reduced uteroplacental blood volume was found to lead to deeper decelerations only. The model response in several nerve blocking simulations was similar to experimental findings by Martin et al. [18], indicating a correct balance between vagal and sympathetic reflex pathways

Clinical use of electrohysterography during term \labor:a systematic review on diagnostic value, advantages, and limitations

\u3cp\u3eImportance Real-time electrohysterography (EHG)-based technologies have recently become available for uterine monitoring during term labor. Therefore, obstetricians need to be familiar with the diagnostic value, advantages, and limitations of using EHG. Objective The aims of this study were to determine the diagnostic value of EHG in comparison to (1) the intrauterine pressure catheter (IUPC), (2) the external tocodynamometer (TOCO), and (3) in case of maternal obesity; (4) to evaluate EHG from users' and patients' perspectives; and (5) to assess whether EHG can predict labor outcome. Evidence Acquisition A systematic review was performed in the MEDLINE, EMBASE, and Cochrane library in October 2017 resulting in 209 eligible records, of which 20 were included. Results A high sensitivity for contraction detection was achieved by EHG (range, 86.0%-98.0%), which was significantly better than TOCO (range, 46.0%-73.6%). Electrohysterography also enhanced external monitoring in case of maternal obesity. The contraction frequency detected by EHG was on average 0.3 to 0.9 per 10 minutes higher compared with IUPC, which resulted in a positive predictive value of 78.7% to 92.0%. When comparing EHG tocograms with IUPC traces, an underestimation of the amplitude existed despite that patient-specific EHG amplitudes have been mitigated by amplitude normalization. Obstetricians evaluated EHG tocograms as better interpretable and more adequate than TOCO. Finally, potential EHG parameters that could predict a vaginal delivery were a predominant fundal direction and a lower peak frequency. Conclusions and Relevance Electrohysterography enhances external uterine monitoring of both nonobese and obese women. Obstetricians consider EHG as better interpretable; however, they need to be aware of the higher contraction frequency detected by EHG and of the amplitude mismatch with intrauterine pressure measurements. Target Audience Obstetricians and gynecologists, family physicians. Learning Objectives After completing this activity, the learner should be better able to interpret the physiology of uterine contractions, relate the diagnostic value of electrohysterography (EHG) traces to intrauterine pressure catheter and tocodynamometer, examine how the performance of the external uterine monitoring techniques is affected by maternal obesity, distinguish the advantages and limitations of EHG-based monitoring from users' and patients' perspectives, and propose uses for EHG uterine contraction monitoring and other (future) applications of EHG.\u3c/p\u3

Insight into variable fetal heart rate decelerations from a mathematical model

During labor and delivery, variable decelerations in the fetal heart rate (FHR) are commonly seen on the cardiotocogram (CTG) that is used to monitor fetal welfare. These decelerations are often induced by umbilical cord compression from uterine contractions. Via changes in oxygenation and blood pressure, umbilical cord compression activates the chemo- and baroreceptor reflex, and thus affects FHR. Since the relation between the CTG and fetal oxygenation is complex, assessment of fetal welfare from the CTG is difficult. We investigated umbilical cord compression-induced variable decelerations with a mathematical model. For this purpose, we extended our model for decelerations originating from caput compression and reduced uterine blood flow with the possibility to induce umbilical venous, arterial and total cord occlusion. Model response during total occlusion is evaluated for varying contractions (duration and amplitude) and sensitivity of the umbilical resistance to the uterine pressure. A clinical scenario is used to simulate a labor CTG with variable decelerations. Simulation results show that fetal mean arterial pressure increases during umbilical cord occlusion, while fetal oxygenation drops. There is a clear relation between these signals and the resulting FHR. The extent of umbilical compression and thus FHR deceleration is positively related to increased contraction duration and amplitude, and increased sensitivity of the umbilical resistance to uterine pressure. No relation is found between contraction interval and FHR response, which can probably be ascribed to the lack of catecholamines in the model. The simulation model provides insight into the complex relation between uterine pressure, umbilical cord compression, fetal oxygenation, blood pressure and heart rate. The model can be used for individual learning, and incorporated in a simulation mannequin, be used to enhance obstetric team trainin

Interventions for intrauterine resuscitation in suspected fetal distress during term labor:A systematic review

\u3cp\u3eIMPORTANCE: Intrauterine resuscitation techniques during term labor are commonly used in daily clinical practice. Evidence, however, to support the beneficial effect of intrauterine resuscitation techniques on fetal distress during labor is limited and sometimes contradictory. In contrast, some of these interventions may even be harmful.\u3c/p\u3e\u3cp\u3eOBJECTIVE: To give insight into the current evidence on intrauterine resuscitation techniques. In addition, we formulate recommendations for current clinical practice and propose directions for further research.\u3c/p\u3e\u3cp\u3eEVIDENCE ACQUISITION: We systematically searched the electronic PubMed, EMBASE, and CENTRAL databases for studies on intrauterine resuscitation for suspected fetal distress during term labor until February 2015. Eligible articles and their references were independently assessed by 2 authors. Judgment was based on methodological quality and study results.\u3c/p\u3e\u3cp\u3eRESULTS: Our literature search identified 15 studies: 4 studies on amnioinfusion, 1 study on maternal hyperoxygenation, 1 study on maternal repositioning, 1 study on intravenous fluid administration, and 8 studies on tocolysis. Of these 15 research papers, 3 described a randomized controlled trial; all other studies were observational reports or case reports.\u3c/p\u3e\u3cp\u3eCONCLUSIONS AND RELEVANCE: Little robust evidence to promote a specific intrauterine resuscitation technique is available. Based on our literature search, we support the use of tocolysis and maternal repositioning for fetal distress. We believe the effect of amnioinfusion and maternal hyperoxygenation should be further investigated in properly designed randomized controlled trials to make up the balance between beneficial and potential hazardous effects.\u3c/p\u3

Prediction of pre-eclampsia by maternal characteristics : A case-controlled validation study of a Bayesian network model for risk identification of pre-eclampsia

Brief Introduction: Pre-eclampsia (PE) is worldwide a leading and rising cause of maternal and perinatal morbidity and mortality. As PE remains a serious and poorly understood complication of pregnancy, it is necessary to recognize the disease before it threatens the survival of mother and fetus. A validated tool that allows real-time maternal risk stratification is needed to guide care. A recent advanced model for pre-eclampsia presented in Velikova et al. 2014 provides that potential. In contrast to the previous study where the testing with this model was done with data for high-risk pregnancies, in this study we aimed at evaluating the capability of the BN model for pre-eclampsia, by looking at the predictions for normal and pre-eclamptic pregnancies. Materials & Methods: The model is based on a Bayesian network methodology, which has been successfully applied for clinical problems. A Bayesian network (BN) is a statistical model that represents a set of variables (e.g. risk factors, diseases and symptoms) and their dependencies by means of a graph and probability distributions. The advantage of a Bayesian network is that it can be used to make personalized predictions, for example for the development or presence of a disease, by entering patient-specific data. We validated the BN model for PE (PE model) in a retrospective case-control study. 10 women diagnosed with PE admitted to the obstetric high care ward of a tertiary care center were enrolled. Their characteristics were matched with 10 pregnant women without any illness. We collected pregnancy data that was relevant for the model, including: (i) risk factors: age; BMI; smoking; parity; twin pregnancy; family history of PE; previous history of PE; preexisting vascular disease; preexisting renal disease; anti-phospholipid syndrome; diabetes mellitus, (ii) medication and measurements from 10 standard check-ups during the pregnancy: blood pressure, protein-to-creatinine ratio, serum creatinine and hemoglobin and medication and (iii) the outcome variable: whether or not preeclampsia is present. PE risk estimation from the model for each patient was compared to PE development. Model performance was assessed by means of the area under the receiver operating characteristic (ROC) curve (AUC). Clinical Cases or Summary Results: Throughout pregnancy, the PE model predicted a high absolute risk for PE in 9 out of 10 PE patients versus 2 out of 10 non-preeclamptic women. This is shown in Figure 1. Each pregnancy week shows the number of patients that has not delivered yet, the color indicating whether they are ultimately diagnosed with PE (red) or not (green). The predicted risk by the model is indicated with a percentage (y-axis) for each patient at each gestational week (x-axis). ROC curves and PE-risk cut-offs were calculated for different gestational weeks. This resulted in AUC score at 24 weeks of 0.895, at 28 weeks of 1.000, at 32 weeks of 0.986, at 36 weeks 1.000, at 38 weeks of 0.375, at 40 weeks of 1.000. Concluding, we find high AUC scores, except for the prediction at 38 weeks of gestation, due to missing data. Therefore no cut-off value was calculated for week 38. Sensitivity, specificity, the positive predictive value (PPV) and negative predictive value (NPV) of the PE model are as well calculated per week of gestation, except for week 38. The sensitivity of the PE model is 100% at each pregnancy week. We find a specificity of 83%, 100%, 91%, 100% and 100% at 24, 28, 32, 36 and 40 weeks, respectively. Thus, 8-17% of women without PE will be screened as having an increased risk. The PPV is calculated as 33%, 100%, 83%, 100% and 100% at 24, 28, 32, 36 and 40 weeks, respectively. The NPV is calculated as 100% at each pregnancy week. Conclusions: When data is available in early pregnancy, the PE model is able to distinguish between PE and non-PE pregnant women and able to predict a higher risk for the diagnosed patients. In particular, at gestational week 12 the chance for PE was twice or higher for PE patients than for 8 of the non-PE pregnant women, and for weeks 16-24 this chance for PE patients was up to eight times higher for the PE patients. This is a particularly important result given the aim of a timely identification of women at risk, which is to facilitate much targeted monitoring. Despite the fact not all data was available for all pregnancy checkups, the PE model was still able to compute the individual, absolute risk for pre-eclampsia. Although for some patients PE was only predicted late in pregnancy, this was for all patients before or at latest at the same moment of clinical diagnosis. However, we expect that prediction will improve when all measurements are available from the pregnancy checkups. From the model it follows that a dynamic cut-off is needed that increases with pregnancy duration. Current results are promising. We propose to perform an RCT with a larger number of patients to establish this cut-off curve with more accuracy and to validate the PE model prospectively. Once validated, the model can assist in early PE diagnosis and thus allow early treatment of PE. The PE model can be integrated in e-health applications to allow real-time monitoring of pregnant women anywhere. By this way we can personalize the healthcare during pregnancy. (Figure presented

Practice variation in the management of intrapartum fetal distress in The Netherlands and the Western world

\u3cp\u3eOBJECTIVE: Solid evidence on the effect of intrauterine resuscitation on neonatal outcome is limited, and superiority of one intervention over the others is not clear. We therefore surveyed the clinical practice variation in fetal monitoring and the management of fetal distress during labor, in Dutch labor wards. In addition, we have compared recommendations from international guidelines.\u3c/p\u3e\u3cp\u3eSTUDY DESIGN: We conducted a survey among all 86 Dutch hospitals, using a questionnaire on fetal monitoring and management of fetal distress. In addition, we requested international guidelines of 28 Western countries to study international recommendations regarding labor management.\u3c/p\u3e\u3cp\u3eRESULTS: The response rate of the national survey was 100%. Labor wards of all hospitals use CTG for fetal monitoring, 98% use additional fetal scalp blood sampling, and 23% use ST-analysis. When fetal distress is suspected, oxytocin is discontinued and tocolytic drugs are applied in all hospitals. Nearly all hospitals (98%) use maternal reposition for fetal resuscitation, 33% use amnioinfusion, and 58% provide maternal hyperoxygenation. Management is mainly based on the Dutch national guideline (58%) or on local guidelines (26%). Eight international guidelines on fetal monitoring were obtained for analysis. Fetal scalp blood sampling facilities are recommended in all the obtained guidelines. Use of ST-analysis is recommended in three guidelines and advised against in three guidelines. Five guidelines also advised on intrauterine resuscitation: discontinuation of oxytocin and use of tocolytic drugs was advised in all guidelines, amnioinfusion was recommended in two guidelines and advised against in two guidelines, whereas maternal hyperoxygenation was recommended in two guidelines and advised against in one guideline.\u3c/p\u3e\u3cp\u3eCONCLUSION: Nationwide clinical practice, and recommendations from international guidelines agree on the use of fetal scalp blood sampling in addition to cardiotocography during labor. The opinion on the use of ST-analysis differs per clinic and per guideline. Discontinuation of oxytocin, administration of tocolytic drugs and maternal repositioning are rather uniform, on national and international level. However, there is a large variation in the use of amnioinfusion and maternal hyperoxygenation, which may be explained by the contradictory recommendations of the different guidelines.\u3c/p\u3