If umbilical cord is clamped 3 min after birth or later, or if the newborn is kept below the placenta before cord clamping, 35 ml/kg may flow into the neonate. Another 45 ml of blood per kg of fetal weight contained in the placenta (9). Before birth the fetus contains a blood volume of approximately 70ml/kg. Blood transfusion from the placenta to the neonate occurs when the umbilical cord is clamped at sometime after 5 seconds of birth. Several previous studies have been addressed the effect of placental transfusion on the development of neonatal Polycythemia(4,23). thereby, suggesting the use of cord blood hematocrits for screening of neonatal Polycythemia (16). Blood groups found good correlation between cord hematocrit levels and peripheral venous hematocrit levels by age 2 h. Shohat and Ramamurthy (16,21) demonstrated a marked increase in the hematocrit and blood viscosity during the first hours of postnatal life and suggested that the time of blood sampling should be considered in the diagnosis of polycythemia and hyperviscosity. Neonatal polycythemia may be associated with a high incidence of developmental and neurological abnormalities at one to seven years of age (3). Introduction Polycythemia defined as a hematocrit over 0.65, affects 2-6% of all newborn infants (15,24). The increased whole blood viscosity is the result of rise in plasma viscosity and RBCs aggregation, together with the lowered red cell deformity.Ĭonclusion: The moderate rise in blood viscosity in neonates with late cord clamping was not associated with clinical symptoms of impaired organ perfusion. Results: Late cord clamping results in a moderate rise of blood viscosity mainly due to marked increase of hematocrit. The results were compared with 10 healthy infants (10 months age). Fetal blood volume of placenta was also determined. Blood samples were tested for CBC, Differential blood count, C-reactive protein (CRP), bilirubin, hematocrit, total plasma protein, plasma fibrinogen, IgG, plasma albumin, HbF, RBCs aggregation, RBC deformity, blood and plasma viscosity. Blood samples were taken from placenta at zero time and from neonates at zero, 2 hours, 24 hours and 5 days after delivery. Umbilical cord clamping was performed within 15 seconds in 15 newborns and after 3 minutes of delivery in the other 15 newborns. Subjects and Methods Thirty full term newborns delivered normally through vagina were selected. Objective: To study the effects of early and late cord clamping on neonatal blood viscosity.
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