Fetal Blood Cell Production: Liver, Spleen & Bone Marrow

Liver: Fetal liver is the primary site of hematopoiesis until the third trimester. It produces red blood cells (RBCs), white blood cells (WBCs), and platelets.

Spleen: The spleen also plays a role in hematopoiesis, producing RBCs and WBCs.

Bone Marrow: During the third trimester, hematopoiesis shifts from the liver and spleen to bone marrow. Bone marrow becomes the primary site of hematopoiesis after birth and continues throughout life.