The Human Hemoglobins in Health and Disease

Abstract

Fetal Hemoglobin in Normal and Pathologic ConditionsAlthough fetal hemoglobin has been recognized since 1866¹⁹ its occurrence in normal and pathologic states has been extensively investigated only during the past few years.^{20,30,73,114, 116 117 118 119 120 121 122 123 124 125} Hgb F appears at the time red cells are first developed in the fetus and is probably the only type of blood pigment present until Hgb A production starts at about the fifth or sixth intrauterine month. At birth 55 to 85 per cent of the hemoglobin is in the embryonic form, after which there is a rapid decrease to normal adult levels¹²⁰ (Fig. 6). Contrary to numerous . . .