Transition from fetal to postnatal circulation
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fetal to postnatal circulation





Question Authority




Contact: Eileen Nicole Simon
Clamping the umbilical cord at birth is a human invention, and has long been the subject
of controversy.  It is no doubt instinctive for most obstetricians and midwives to wait for
an infant's first breath before clamping the cord; until the 1980s this was explicitly stated
in most textbooks of obstetrics and midwifery.  Many texts also taught that the cord
should not be cut until pulsations in it had ceased.
Pulsations in the cord are from the infant's heart, pumping blood to the placenta for
oxygen and nutrients.  Valves in the heart that direct blood flow to the placenta close
after full inflation of the lungs, but this can take up to 20 minutes or more after birth.
In 1773, Dr. Charles White commented:
"Can it possibly be supposed that this
important event, this great change which
takes place in the lungs, the heart, and the
liver, from the state of a foetus, kept alive by
the umbilical cord, to that state when life
cannot be carried on without respiration,
whereby the lungs must be fully expanded
with air, and the whole mass of blood instead
of one fourth part be circulated through them,
the ductus venosus, foramen ovale, ductus
arteriosus, and the umbilical arteries and vein
must all be closed, and the mode of
circulation in the principal vessels entirely
altered - Is it possible that this wonderful
alteration in the human machine should be
properly brought about in one instant of time,
and at the will of a by-stander?"
Charles White (1728-1813)
White C (1773) A Treatise on the Management
of Pregnant and Lying-In Women.
Canton, MA:
Science History Publications, 1987, p 45
Available from:
Posted: February 27, 2006
(a work in progress)
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