As embryological development continues haematopoiesis shifts from the yolk sac and AGM to the foetal liver (and [[Spleen - Anatomy & Physiology|spleen]]). Haematopoietic areas form in the [[Liver - Anatomy & Physiology|liver]] which become the main haematopoietic organ in the body. [[Erythropoiesis|Erythropoiesis]] is the predominant process but some [[Leukopoiesis|leukopoiesis]] occurs so the foetal liver can be considered a [[:Category:Primary Lymphoid Tissue| primary lymphoid organ]].