RT Book, Section
A1 Brumbaugh, Jane E.
A1 Gourley, Glenn R.
A2 Stevenson, David K.
A2 Maisels, M. Jeffrey
A2 Watchko, Jon F.
SR Print(0)
ID 56321563
T1 Chapter 3. Bilirubin and Its Various Fractions
T2 Care of the Jaundiced Neonate
YR 2012
FD 2012
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-176289-2
LK accesspediatrics.mhmedical.com/content.aspx?aid=56321563
RD 2024/04/19
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).