The Pinard stethoscope is a low-tech bit of fetal monitoring technology. It shares its shape and essential function with the earliest stethoscopes, in that it is simply a hollow tube, designed to put some distance between the ear of the listener and the body from which the sound is originating. The absence of techno-gizmo wizardry (such as the bits that go into making a fetal Doppler) means that the listener gets to hear the unadulterated sound made by the fetal heart. The Pinard is not often used, and some skill is required to use it for fetal monitoring.
A recently published paper reports on focus group interviews conducted with Norwegian midwives who regularly used a Pinard in their current or historical practice (Engelhart, et al., 2022). The researchers explored the skills of Pinard use and midwives’ experiences and practices of using a Pinard for fetal monitoring. 21 midwives took part. They ranged in age from 34 to over 80 years, and had between 2.5 and 40 years of midwifery experience, with the majority having over 30 years of experience. Reflexive thematic analysis was used to make sense of the data.
The introduction of CTG monitoring was not universally welcomed:
“I remember when the first CTG machines came, we did not want to use them, we threw them out in the hallway, along with the new technical beds.”p. 4
Midwives described preferring the Pinard when making the initial assessment of the woman, particularly when women presented with reduced fetal movement. This avoided the possibility of mistaking maternal heart sounds for fetal (which occurs more often with Dopplers). The midwives reported that using the Pinard helped bring calm and gave them time to compose their thoughts if they suspected fetal demise. A fetal Doppler was preferred for women who were overweight, during the second stage of labour, and in certain positions where it was difficult to use the Pinard (such as squatting).
Midwives indicated that the best way to gain competence with the Pinard was to use it regularly. In addition to listening to the baseline rate, and for the presence of accelerations, midwives described a change in the timbre and strength of the fetal heart sounds that generated concern for fetal wellbeing. Descriptions of abnormal timbre included thin, split, not clean, or choppy. Assessment of the strength and timbre of the fetal heart sounds were much easier with the Pinard than with a Doppler.
Midwives reported that the Pinard provided them with a sense of safety and enhanced their connection with the birthing woman. The detailed abdominal palpation required to place the Pinard appropriately provided midwives with additional information about fetal size and position, permitting them to track the rotation and descent of the fetus during labour. Midwives combined other information about fetal wellbeing (such as the colour of the liquor) with their assessment of the fetal heart using the Pinard to come to an overall assessment of the fetus.
My own experience of using the Pinard is limited, confined to antenatal use, and mostly when teaching medical students. I was particularly interested to read the descriptions of aspects of the fetal heart sounds that are particularly tricky to hear with a Doppler and that may contribute to a more wholistic assessment of fetal wellbeing. Modifications in the timbre and strength of the fetal heart sounds presumably relate to changes in fetal blood pressure and stroke volume, features that we are not able to assess at all with the CTG. These seem like useful measures to have in our tool kit, but the Pinard has been almost completely abandoned in contemporary practice. In our push to use the latest and greatest in technology, I wonder what else we may have lost along the way?
Engelhart, C. H., Nilsen, A. B. V., Pay, A. S. D., Maude, R., Kaasen, A., & Blix, E. (2022, Feb 19). Practice, skills and experience with the Pinard stethoscope for intrapartum foetal monitoring: Focus group interviews with Norwegian midwives. Midwifery, 108, 103288. https://doi.org/10.1016/j.midw.2022.103288