""Very early clamping results in less than physiologic blood volume. The
normal, term child routinely survives, but clamping the cord of a
compromised child before ventilation is riskier. Initial aeration of the
lungs causes reflex dilatation of pulmonary arterioles and a massive
increase in pulmonary blood flow. Placental transfusion normally supplies
this volume. Clamping the cord before the infant's first breath results in
blood being sacrificed from other organs to establish pulmonary perfusion.
Fatality may result if the child is already hypovolemic. 

Because placental transfusion patterns vary widely, it is futile to attempt
to give the newborn the "right" amount of blood by clamping at a set time
after birth. However, it is extremely likely that the infant will have
less-than-optimal blood volume if the cord is clamped before the lungs are
ventilated. 

In clinical practice, late clamping produces a high hematocrit, high blood
pressure, and vasodilatation to accommodate the large volume of blood. These
latter two factors should increase tissue perfusion. In searching the
literature, I was unable to find any documented case of hyperviscosity
syndrome in which the cord was clamped late, although I did find many
documented cases of late clamping involving normal newborns with high
hematocrits. 

There are, however, many documented cases of hyperviscosity syndrome with
high hematocrits (e.g., cases involving gestational diabetes or
postmaturity) in which the cord was clamped before physiologic cord closure,
thus creating low blood volume, low blood pressure, and vasoconstriction
coupled with the polycythemia. The inadequate tissue perfusion is blamed on
the high hematocrit, when the root cause of the hyperviscosity syndrome is
hypovolemic vasoconstriction enforced to the fourth power.
-excerpted from George M. Morley, MB., CH. B, Cord Closure: Can Hasty
Clamping Injure the Newborn? July 1998 OBG Management."  

Sent by Gloria Lemay, Vancouver BC

www.consciouswoman.org


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