Text Box: THE ETIOLOGICAL CAUSES OF NEONATAL ICTERUS Kuanyshbekova R.T. Kazakh state institute of doctors’ improvements Kazakhstan, Almaty An objective of present research is determination the etiological structure children’s neonatal icterus. 296 newborn children (and their mothers) with various degree of icteric syndrome expressiveness were under observation. Newborn with an icterus (and their mothers) were examined for seven most wide-spread prenatal infections (PI), namely: chlamidiosis, cytomegaly, syphilis, toxoplasmosis, listerosis, hepatitis viruses B and C. Prenatal infections (PI) was diagnosed on the basis of serological, immunological, bacteriological, cytologic tests and results of polymerase chain reaction. The results of observation have determined the fact that PI is the reason of neonatal icteruses in 61,2% of cases: cytomegaly infection - in 13,1%, chlamidiosis - in 12,8 %, lues - in 9,9 %, hepatitis B - in 7,3 %, toxoplasmosis - in 6,1 %, listerosis - in 5,6 %, hepatitis C - in 5,3 % of cases. The biochemical tests have shown the bilirubin augmentation from 142 up to 260 mc.mole/l with prevalence of indirect fraction, enzymes’ activity rising of cholestasia, gammaglutamiltranspeptidase and alkaline phosphatase, and also glutathione-s- transferase level elevation. Ultrasound investigations of liver have revealed parenchyma diffuse changes (58,1 %), phenomenons of a cholestasia (60,7 %), and also inherent anomalies bile-excreting system (17,8 %) cases. Thus prenatal infections at children are the cause of development at fertus of enzymopathies, congenital anomalies of bile-excreting system, phenomenons, of cholestasia causing in turn development of an icteric syndrom at newborn children. 2340