Concentration de la bilirubine dans le liquide amniotique et indice de Liley au cours du deuxieme trimestre de la grossesse

Currently, the management of the pregnancy complicated by rhesus sensitization is less invasive: genotype RHD of the fetus is determined by PCR on fetal DNA from maternal plasma and the severe fetal anemia is detected by Doppler ultrasonography. Nevertheless, the amniocentesis is still realized for RHD determination by PCR on amniotic cells and for amniotic-fluid ΔDO450 measurement. This parameter interpreted with the Liley's or the Queenan chart predicts the gravity of the haemolytic disease of the fetus and newborn. Blood or meconium contaminations decrease the reliability of the test. In addition of the ΔDO450, we determine bilirubine concentration by spectrophotometry using the formula of Clin Chim Acta 12 (1965) 67-74. We established references limits of the two tests according gestational age on the basis of percentile 95 of our population (n = 1200). Limits for ΔDO405 in our laboratory were in agreement with the limit between the « indeterminate » and « Rh positive affected » zone of Queenan's chart. The two tests interpreted according to our standards are in agreement in 96.5% of the cases.