Liquor Bilirubin Levels in Normal Pregnancy: A Basis for Accurate Prediction of Haemolytic Disease

Abstract

Liquor amnii from 29 normal Rh-positive subjects was examined in order to establish normal bile pigment levels. In 25 of these a pigment/protein ratio was calculated to avoid the effects of variations of liquor volume on pigment concentration. Similar ratios from 22 Rh-negative women with antibodies gave a good indication of the severity of haemolytic disease. It is concluded that deductions from any method of simple estimation of pigment concentration percentage may suggest grossly inaccurate prognoses because of variation in liquor volume, and that a pigment/protein ratio is a much more accurate guide. At Queen Charlotte's Hospital the pigment-protein ratio is found particularly useful in helping to avoid interfering with rhesus-negative or mildly affected foetuses. © 1967, British Medical Journal Publishing Group. All rights reserved.