Immunoreactive transferrin receptor in sera of pregnant women

Immunoreactive transferrin receptors in sera of 90 pregnant women of various gestational periods were investigated. The mean concentrations of the serum transferrin receptor in normal males and females were 251 +/- 94 ng/ml and 256 +/- 99 ng/ml, respectively. Serum transferrin receptor levels in pregnant women did not show a significant increase in the early stage of gestation. However, a rapid elevation of the mean concentration of transferrin receptor was observed after 20 weeks of pregnancy. The apparent increase with gestation period suggests that this immunoreactive receptor in the sera of pregnant women is derived from the placental syncytiotrophoblast and reflects the activity of maternofetal iron transport.