Where is blood made in utero

  • Day 18 to 3m in yolk sac
  • 3m to 6m liver and spleen
  • 6m onward Bone marrow

Haemoglobin:

(\alpha^2) + (\gamma^2) = Fetal Hb

(\alpha^2) + (\beta^2) = Adult Hb

(\alpha^2) + (\delta^2) = HbA(_2)

How do RBC differ in neonates

  • Different Hb (Hb-F completely gone by 6 months)
  • Polycythaemic
  • (\uparrow) reticulocytes
  • (\uparrow) nucleated RBCs - gone after 3-4 days, if still present after indicates baby struggled in womb/placental hypoxia