Electrohysterography. A promising alternative for monitoring contractions

Monitoring contractions during labour using the external tocodynamometer can be difficult or even impossible, and using the invasive intrauterine pressure catheter is associated with rare but serious complications. A new non-invasive technique is currently available: electrohysterography (EHG). This technique converts the electrical activity of the uterine muscle into a legible tocogram. The EHG signal has a high correlation with the intrauterine pressure and provides a more accurate assessment of uterine activity compared to external tocodynamometry. EHG is suitable for women in labour with failure of the external tocodynamometer. In clinical practice EHG also appeared to report a more detailed tocographic waveform, like hypertonia or unorganized electrical uterine activity. However, its signal quality depends on adequate skin preparation and correct positioning of the electrodes on the maternal abdomen. Hence, with electrohysterography as noninvasive alternative for uterine monitoring, choosing between safety and accuracy is no longer necessary. Conflict of interest and financial support: ICMJE forms provided by the authors are available online along with the full text of this article.</p

Electrohysterography, a promising alternative for uterine monitoring:5 years later

Electrohysterography, a promising alternative for uterine monitoring: 5 years later.Electrohysterography monitors the electrical activity of the uterine muscle through electrodes on the maternal abdominal wall. It is a non-invasive method for uterine contraction monitoring and has a strong correlation with the invasive intra-uterine pressure catheter. A prospective validation study showed a significant higher sensitivity of electrohysterography compared to external tocodynamometry for uterine contraction detection (p-value &lt; 0.001). Moreover, the sensitivity of electrohysterography appears to be less affected by maternal obesity compared to external tocodynamometry. A clinical pilotstudy comparing electrohysterography and external tocodynamometry during labor, showed no negative effect of electrohysterography on labor outcomes. Recently, technical improvements have been made and electrohysterography has become available in an adhesive electrode patch together with fetal and maternal electrocardiography. Therefore, we expect a successful implementation of electrohysterography in the near future.Electrohysterography monitors the electrical activity of the uterine muscle through electrodes on the maternal abdominal wall. It is a non-invasive method for uterine contraction monitoring and has a strong correlation with the invasive intra-uterine pressure catheter. A prospective validation study showed a significant higher sensitivity of electrohysterography compared to external tocodynamometry for uterine contraction detection (p-value &lt; 0.001). Moreover, the sensitivity of electrohysterography appears to be less affected by maternal obesity compared to external tocodynamometry. A clinical pilotstudy comparing electrohysterography and external tocodynamometry during labor, showed no negative effect of electrohysterography on labor outcomes. Recently, technical improvements have been made and electrohysterography has become available in an adhesive electrode patch together with fetal and maternal electrocardiography. Therefore, we expect a successful implementation of electrohysterography in the near future.</p

Tocogram characteristics of uterine rupture: a systematic review

Purpose: Timely diagnosing a uterine rupture is challenging. Based on the pathophysiology of complete uterine wall separation, changes in uterine activity are expected. The primary objective is to identify tocogram characteristics associated with uterine rupture during trial of labor after cesarean section. The secondary objective is to compare the external tocodynamometer with intrauterine pressure catheters. Methods: MEDLINE, EMBASE, and the Cochrane library were systematically searched for eligible records. Moreover, clinical guidelines were screened. Studies analyzing tocogram characteristics of uterine rupture during trial of labor after cesarean section were appraised and included by two independent reviewers. Due to heterogeneity, a meta-analysis was only feasible for uterine hyperstimulation. Results: Thirteen studies were included. Three tocogram characteristics were associated with uterine rupture. (1) Hyperstimulation was more frequently observed compared with controls during the delivery (38 versus 21 % and 58 versus 53 %), and in the last 2 h prior to birth (19 versus 4 %). Results of meta-analysis: OR 1.68 (95 % CI 0.97–2.89), p = 0.06. (2) Decrease of uterine activity was observed in 14–40 % and (3) an increasing baseline in 10–20 %. Five studies documented no changes in uterine activity or Montevideo units. A direct comparison between external tocodynamometer and intrauterine pressure catheters was not feasible. Conclusions: Uterine rupture can be preceded or accompanied by several types of changes in uterine contractility, including hyperstimulation, reduced number of contractions, and increased or reduced baseline of the uterine tonus. While no typical pattern has been repeatedly reported, close follow-up of uterine contractility is advised and hyperstimulation should be prevented

Tocogram characteristics of uterine rupture: a systematic review

Purpose: Timely diagnosing a uterine rupture is challenging. Based on the pathophysiology of complete uterine wall separation, changes in uterine activity are expected. The primary objective is to identify tocogram characteristics associated with uterine rupture during trial of labor after cesarean section. The secondary objective is to compare the external tocodynamometer with intrauterine pressure catheters. Methods: MEDLINE, EMBASE, and the Cochrane library were systematically searched for eligible records. Moreover, clinical guidelines were screened. Studies analyzing tocogram characteristics of uterine rupture during trial of labor after cesarean section were appraised and included by two independent reviewers. Due to heterogeneity, a meta-analysis was only feasible for uterine hyperstimulation. Results: Thirteen studies were included. Three tocogram characteristics were associated with uterine rupture. (1) Hyperstimulation was more frequently observed compared with controls during the delivery (38 versus 21 % and 58 versus 53 %), and in the last 2 h prior to birth (19 versus 4 %). Results of meta-analysis: OR 1.68 (95 % CI 0.97–2.89), p = 0.06. (2) Decrease of uterine activity was observed in 14–40 % and (3) an increasing baseline in 10–20 %. Five studies documented no changes in uterine activity or Montevideo units. A direct comparison between external tocodynamometer and intrauterine pressure catheters was not feasible. Conclusions: Uterine rupture can be preceded or accompanied by several types of changes in uterine contractility, including hyperstimulation, reduced number of contractions, and increased or reduced baseline of the uterine tonus. While no typical pattern has been repeatedly reported, close follow-up of uterine contractility is advised and hyperstimulation should be prevented

Elektrohysterografie: Een veelbelovend alternatief voor weeënregistratie

Monitoring contractions during labour using the external tocodynamometer can be difficult or even impossible, and using the invasive intrauterine pressure catheter is associated with rare but serious complications. A new non-invasive technique is currently available: electrohysterography (EHG). This technique converts the electrical activity of the uterine muscle into a legible tocogram. The EHG signal has a high correlation with the intrauterine pressure and provides a more accurate assessment of uterine activity compared to external tocodynamometry. EHG is suitable for women in labour with failure of the external tocodynamometer. In clinical practice EHG also appeared to report a more detailed tocographic waveform, like hypertonia or unorganized electrical uterine activity. However, its signal quality depends on adequate skin preparation and correct positioning of the electrodes on the maternal abdomen. Hence, with electrohysterography as noninvasive alternative for uterine monitoring, choosing between safety and accuracy is no longer necessary. Conflict of interest and financial support: ICMJE forms provided by the authors are available online along with the full text of this article

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

Importance 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

Uterine monitoring techniques from patients' and users' perspectives

Objective To evaluate preferences from patients and users on 3 uterine monitoring techniques, during labor. Study Design Women in term labor were simultaneously monitored with the intrauterine pressure catheter, the external tocodynamometer, and the electrohysterograph. Postpartum, these women filled out a questionnaire evaluating their preferences and important aspects. Nurses completed a questionnaire evaluating users' preferences. Results Of all 52 participating women, 80.8% preferred the electrohysterograph, 17.3% the intrauterine pressure catheter and 1.9% the external tocodynamometer. For these women, the electrohysterograph scored best regarding application and presence during labor (p < 0.001). Most important aspects were least likely to harm and least discomfort. Of 57 nurses, 40.4% preferred the electrohysterograph, 35.1% the external tocodynamometer, and 24.6% had no preference, or replied that their preference is subject to situation and patient. Conclusion Patients prefer the electrohysterograph over the external tocodynamometer and the intrauterine pressure catheter, while healthcare providers report ambiguous results