What FHR abnormalities should IA detect?
It is important to remember that the main asset of IA is its “simplicity” arising from the deliberate intention to detect a limited number of most important FHR abnormalities in low risk cases. This also accounts for its advantage over CTG namely lower medical/operative intervention. Occam’s Razor (law of parsimony) is a well-established scientific principle implying that (unnecessary) complexity burdens practitioners of science reducing validity and performance.12,13 Clinicians facing complex multi-faceted problems need to make optimum use of their attention ‘bandwidth’ to minimise errors and facilitate appropriate timely decisions. Midwives need to be able to devote more time and attention to broader holistic care to normal women in low risk labours. Hence, the safe practice of IA stemming mainly from the British obstetrics aimed to detect the two most important FHR parameters namely the baseline and late decelerations, as the latter generally have the most significant correlation with fetal hypoxemia/acidemia.1 This has been the reason for traditional recommendation of FHR auscultation for 1 minute immediately after a uterine contraction.1-3 The detailed information/accuracy gained from CTG cannot be expected from IA and indeed seems unnecessary at least in low risk cases as a pragmatic compromise.1-4,6 There is good agreement that IA is not expected to detect baseline FHR variability.1-4Descriptions like ‘timber, strength and cadence’ of fetal heart sounds7 with Pinard stethoscope (or Doppler-device) have been rightly confined to the history. Significant rhythm irregularities easily heard are obvious exception. Specific detailed explanation about how to detect the two abnormalities by IA guidelines would bestow added confidence and assurance to the nurse-midwives.