Normal Hemoglobin Embryonic Hemoglobin Hemoglobin produced in the blood islands in the embryonic yolk sac during the mesoblastic stage of gestation. There are four different embryonic hemoglobins, Hemoglobin Gower 1, Hemoglobin Gower 2, Hemoglobin Portland 1 and Hemoglobin Portland 2. Request inclusion into NCIT below "Hemoglobin"/"Normal Hemoglobin". Add sub-classes: Hemoglobin Gower 1 Hemoglobin Gower 2 Hemoglobin Portland 1 Hemoglobin Portland 2 None Hemoglobin Epsilon R Al-Mufti, H Hambley, F Farzaneh, KH Nicolaides Haematologica Jan 2000, 85 (7) 690-693;