Maternal serum levels of human chorionic somatotropin correlates with transferrin and erythropoietin in pregnancy

During pregnancy, plasma levels of erythropoietin (EPO) and transferrin (TSF) show a gradual increase till term, when a slight decrease occurs. Human chorionic somatotropin (hCS) is a peptide hormone with a direct effect on the function of the syncytiotrophoblast and on the mass of functional placental tissue. In order to understand the relationships between the placental functions, maternal erythropoiesis and iron transfer to the fetus, the relationships between EPO and hCS and between TSF and hCS were investigated. A group of healthy pregnant women (n = 190) attending the Obstetric Clinic of the University of Siena were studied. They were between 18 and 43 weeks pregnant. A single blood sample was taken from each patient by radial vein puncture on admission into the clinic before the beginning of any therapy, for the determination of haemoglobin, EPO, fer-ritin, serum iron, TSF and hCS. The highest correlation was that between hCS and TSF (r = 0.336, p < 0.0001). This correlation was significant in anaemic patients and lost its significance in non-anaemic patients. In our study, we also found a significant relationship between hCS and logEPO (r = 0.195; p < 0.01) which reached an elevated significance over the entire survey, but did not reach statistical significance in anaemic women. We hypothesise that in pregnancy chorionic villi develop a great capacity to respond to pathological maternal events with the result of regulating the transport of iron, the oxygen tension and the maternal-fetal transfer of oxygen through haemoglobin. Evidently, the response of the villi serves to balance the lack of iron in favour of the fetus, probably through a mechanism that links the variations of the iron transport on the maternal side and the increased use on the fetal side through a dynamic and consensual response by the chorionic villi. Copyright © 2002 S. Karger AG, Basel.