From the Guidelines
Doppler ultrasonography is the preferred method for monitoring fetal heart rate compared to fetoscope due to its earlier detection capability, ease of use, and reliability, as evidenced by a recent study 1 that highlights the importance of Doppler assessment in fetal growth restriction.
Key Points
- Doppler devices can detect fetal heart motion as early as 8-12 weeks gestation with accuracy rates of 95-100% 1.
- Fetoscopes, on the other hand, can only detect fetal heart sounds after about 18-20 weeks and require more skill to use properly 1.
- Doppler ultrasonography is less affected by background noise or maternal obesity, making it a more reliable choice for monitoring fetal heart rate 1.
- The use of umbilical arterial Doppler assessment has been shown to decrease the likelihood of labor induction, cesarean delivery, and perinatal deaths in high-risk pregnancies with suspected intrauterine growth restriction (IUGR) 1.
Clinical Implications
- Doppler ultrasonography should be the primary method for monitoring fetal heart rate in most clinical situations due to its superior detection capabilities and reliability.
- Fetoscopes may still be useful in low-resource settings or as a backup when electronic devices are unavailable.
- The choice of monitoring method should be based on the individual patient's needs and the availability of resources.
- Clinicians should be aware of the limitations and advantages of each method to provide the best possible care for their patients.
Evidence-Based Recommendation
- Doppler ultrasonography is the recommended method for monitoring fetal heart rate due to its earlier detection capability, ease of use, and reliability, as supported by the most recent and highest quality study 1.
From the Research
Comparative Efficacy of Doppler and Fetoscope
- The Doppler is thought to be more comfortable and effective compared to the fetoscope for assessing the fetal heart rate (FHR) during labor 2.
- Midwives' preferences of FHR monitoring devices are influenced by the level of device training, experience with using a device, reliable measurements, and convenience and comfort during use 2.
- A study comparing the accuracy and reliability of fetal heart rate identification from maternal abdominal surface electrodes and Doppler ultrasound found that the abdominal fetal ECG had a lower root mean square error than ultrasound (5.2 vs. 10.6 bpm, p < 0.001) 3.
- Another study found that intrapartum FHR using Electronic Uterine Monitoring (EUM) is both valid and accurate, yielding higher correlations with internal scalp electrode monitoring than external Doppler (99.0% versus 96.6%, p < .001) 4.
Accuracy and Reliability
- A randomized controlled trial found that abnormalities in fetal heart rate were more reliably detected by Doppler ultrasonography than with Pinard stethoscope, and its use resulted in good perinatal outcome 5.
- A study on heart rate estimation and validation algorithm for fetal phonocardiography found that the proposed algorithm provides good accuracy overall but is sensitive to the noises in the recording environment that influence the quality of the signals 6.
- The use of Doppler ultrasonography was found to result in better neonatal outcomes, including lower rates of hypoxic ischemic encephalopathy and neonatal seizures, compared to the use of Pinard stethoscope 5.
Clinical Implications
- The choice of device for fetal heart rate monitoring should be based on the level of training and experience of the healthcare provider, as well as the availability and reliability of the device 2.
- The use of Doppler ultrasonography and other non-invasive technologies may provide a good alternative to traditional methods of fetal heart rate monitoring, particularly in low-resource settings 3, 4, 5.
- Further research is needed to evaluate the effectiveness and accuracy of different devices and technologies for fetal heart rate monitoring in various clinical settings 6.