[Phase contrast microscopy studies of the urine of newborn infants]

Phase contrast microscopy allows a much better identification of the urinary sediment constituents than conventional bright field microscopy. The urinary sediment of 100 neonates admitted in a care unit has been examined by phase contrast microscopy. In all cases, squamous cells are far more numerous in newborn girls than in boys. An important rate of abnormal sediments has been observed: in 40 patients cytologic symptoms of renal ischaemia have been observed (hyaline or granulous casts and renal tubular cells, but red blood cells are uncommon). Numerous uric acid cristals were persent in 22 newborns, in correlation with a prolonged perinatal hypoxia. A considerable bacteriuria was seen in 21 neonates, without concomitant leucocyturia. In conclusion, only 20% of the investigated neonates had a normal urinary sediment.