LAUSR

In several countries, confidential enquiry into maternal deaths, combined with rigorous classification, has become a valued method to improve the quality of maternity care. The death of Mrs X (panel) is a case of maternal mortality—ie, “the death of a woman while pregnant or within 42 days of termination of pregnancy...from any cause related to or aggravated by the pregnancy or its management”. However, who would predict that her underlying cause of the death would be classified differently, depending on the country where she died? On May 5, 2017, the UK Confidential Enquiry into Maternal Deaths and the Dutch Audit Committee Maternal Mortality and Morbidity, met in Oxford, UK, to compare maternal deaths in the two countries, identify common lessons for improvement of care, and achieve uniform classification. In the UK, the underlying cause of Mrs X’s death would be described as postpartum haemorrhage after caesarean section. Messages for improving care based on review of her death would be included in the “major obstetric haemorrhage” chapter of the MBRRACE-UK (Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries across the UK) Confidential Enquiry into Maternal Deaths report. In the Netherlands, the chain of morbid events would be traced back to pre-eclampsia as the primary event, which led to caesarean section that, together with possible clotting dysfunction, caused haemorrhage according to the Dutch interpretation. On the basis of the standard terminology in the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), and its application in pregnancy, ICD-Maternal Mortality (ICD-MM), it is difficult to decide who is right. In ICD-MM, underlying cause of death is defined as ”the disease or condition that initiated the morbid chain of events leading to death or the circumstances of the accident or violence that produced a fatal injury”. But where does this chain actually start? Both committees have good reasons to do as they did. The UK classification enables a more pragmatic approach that focuses on the most important lessons for clinical practice, which are related to the management of haemorrhage in Mrs X’s case. The Dutch classification enables a more thorough assessment of underlying pathology, and brings to light indications for obstetric interventions as causes of mortality rather than the interventions themselves. In the eyes of the UK Confidential Enquiry, the latter approach could lead to over-representation of already common pathologies such as pregnancy-related hypertensive disorders. Tracking the chain of events in Mrs X’s case to before the caesarean section could draw attention away from 6 Johnsson LG, Hawkins JE Jr. Degeneration patterns in human ears exposed to noise. Ann Otol Rhinol Laryngol 1976; 85: 725–39. 7 Johnsson LG. Sequence of degeneration of Corti’s organ and its first-order neurons. Ann Otol Rhinol Laryngol 1974; 83: 294–303. 8 Arenas JP, Suter AH. Comparison of occupational noise legislation in the Americas: an overview and analysis. Noise Health 2014; 16: 306–19. 9 Kujawa SG, Liberman MC. Adding insult to injury: cochlear nerve degeneration after “temporary” noise-induced hearing loss. J Neurosci 2009; 29: 14077–85. 10 Liberman MC, Kiang NY. Acoustic trauma in cats. Cochlear pathology and auditory-nerve activity. Acta Otolaryngol Suppl 1978; 358: 1–63. 11 Schmiedt RA, Mills JH, Boettcher FA. Age-related loss of activity of auditory-nerve fibers. J Neurophysiol 1996; 76: 2799–803. 12 Costalupes JA, Young ED, Gibson DJ. Effects of continuous noise backgrounds on rate response of auditory nerve fibers in cat. J Neurophysiol 1984; 51: 1326–44. 13 Viana LM, O’Malley JT, Burgess BJ, et al. Cochlear neuropathy in human presbycusis: confocal analysis of hidden hearing loss in post-mortem tissue. Hear Res 2015; 327: 78–88. 14 Liberman MC, Epstein MJ, Cleveland SS, Wang H, Maison SF. Toward a differential diagnosis of hidden hearing loss in humans. PLoS One 2016; 11: e0162726.