TY - CHAP M1 - Book, Section TI - Chapter 3. Bilirubin and Its Various Fractions A1 - Brumbaugh, Jane E. A1 - Gourley, Glenn R. A2 - Stevenson, David K. A2 - Maisels, M. Jeffrey A2 - Watchko, Jon F. Y1 - 2012 N1 - T2 - Care of the Jaundiced Neonate AB - In the human fetus, as in the adult, biliverdin-IXα and any small amounts of non-IXα isomers that are formed are reduced to the corresponding bilirubins. Of these, bilirubin-IXα is uniquely hydrophobic and lipophilic, and ready to cross the placenta for elimination by the mother. In utero, residual non-IXα isomers too polar to cross the placenta, particularly the IXβ isomer, accumulate and are detectable in bile and meconium by 15 weeks gestation.1 This observation has led some to conclude erroneously that heme catabolism in the fetus yields predominantly the IXβ isomer. The major form of bilirubin generated in infants and adults alike is bilirubin-IXα, and can be measured in various forms (Table 3-1). SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=56321563 ER -