Place for Figures 1, 2, 3
A deceleration can only be imprecisely/subjectively suspected on ‘Pinard
auscultation’; unless one is estimating FHR using ‘multiple count
strategy’. This involves counting heart beats separately for every 10-15
seconds segments during the period of auscultation which is a sound
recommendation by the American College of Nurse-midwives
(ACNM).4 This ‘multiple count strategy’ is certainly
possible (was author’s practice) but difficult; hence rarely practiced
if at all. However, this cumbersome practice becomes completely
unnecessary where Doppler-devices are easily available which are
designed to display temporal variations in FHR. A review article in 2015
highlighted that even with a Doppler-device, special care needs to be
taken in detecting late FHR decelerations because the trough of the
deceleration may have already passed and the recovering FHR (often in
the normal range) immediately after the contraction have been
misinterpreted as ‘accelerations’ leading to procrastination until the
decelerations become severe.6,18 This may be the
likely cause of presumed unexplained birth asphyxia after an apparently
normal IA documentation.6 Following these findings,
the Royal College of Obstetricians and Gynaecologists (RCOG) and Royal
college of Midwives (RCM) are implementing a practice change to commence
auscultation towards the end of the contractions (unpublished RCOG and
RCM document). Unfortunately, this has been implemented with an
erroneous advice that auscultation for 30 seconds after the contraction
would suffice with total 1 minute of counting (unpublished document);
obviously because of preoccupation with ‘counting’ fetal heart tones.
However, extending auscultation to onset of next contraction would be
safer, because in the presence of late decelerations or accelerations,
the accurate baseline is best ascertained by observing the FHR display
on the Doppler-device just before or at the onset next
contraction.6 Additional safeguard would be to confirm
acceleration only when preceded and followed by a normal baseline. The
Doppler-device easily allows extension of the auscultation period very
flexibly beyond 1 minute which seems crucial in confirming periodic FHR
changes (figures 1-3). In contrast, the act of counting heart beats with
Pinard stethoscope reaches its natural but arbitrary end at 1 minute and
could unwarily preclude further flexible extension. Thus, the
Doppler-device FHR display has a major advantage over ‘Pinard’ in
discerning both the meaningful FHR baseline and periodic changes most
importantly the late decelerations.