Mean Liquor Bilirubin Values in Relation to Severity of Hdn

for all grades of severity and even with normal pregnancy. Thereafter, however, the lines diverge and for normal or only mildly affected cases the bilirubin value progressively falls, while for stillbirth and very severe disease it progressively rises. Moderately affected infants fall in the intermediate zone. At all stages of gestation one liquor bilirubin value unless extreme can be misleading, but two consecutive values if falling give reassurance while if high and rising suggest a bad prognosis. This strikes us as a relatively imprecise conclusion, but because one takes action on the basis of bilirubin leveland thereby possibly modifies the severity of the diseasemore precise evaluation is not possible at present. R. C. Whitfield and his colleagues have devised a novel method of evaluating changes in bilirubin level, joining two consecutive bilirubin values and projecting the line to strike their "action line" (Fig. 4).19 This scheme still needs careful evaluation but I doubt whether it is as accurate as has been suggested, for repeated bilirubin estimations in a patient would be expected to fall in a straight line, and in our experience this is not so. None the less, when its limitations have been defined, a scheme of this or similar nature may prove to be valuable.