The haemoglobin of a human foetus

Haemoglobin is the protein that makes red blood corpuscles red and binds easily and reversibly with oxygen. Normal values for haemoglobin are $14-20 \mathrm{~g} / 100 \mathrm{~mL}$ of blood in infants, $13-18 \mathrm{~g} / 100 \mathrm{~mL}$ in adult male and $12-16 \mathrm{~g} / 100 \mathrm{~mL}$ in adult females. Haemoglobin is made up of protein globin bound to the red haem pigment. The globin consists of four polypeptide chains-2 alpha and 2 beta. Foetal haemoglobin does not sickle even in those distined to have sickle cell anaemia, $i e$, haemoglobin of foetus has higher affinity of oxygen than that an adult.