Mid-twentieth century survey of opinion
McCausland et al. (1949) sent a questionnaire to
1,900 diplomates of the American Board of Obstetrics
and Gynecology to determine the usual practice at
that time of handling the umbilical cord at birth.  
Replies from almost every state numbered 1,198 and
revealed that 497 (41.5%) clamped the cord
immediately after birth, 400 clamped the cord within
five minutes after birth, and only 191 waited for
pulsations to cease.  However, 455 practiced stripping
of the cord.

McCausland et al. recommended stripping of the cord,
especially for premature infants, whom they described
as not only underdeveloped, but often in varying
degrees of shock.  They began stripping the cord
because they maintained that there are times when
the condition of the mother or baby made it
inadvisable to wait for the cord to stop pulsating, but
they pointed out that giving a transfusion via
hypodermic syringe to a baby in an incubator was
difficult and traumatic.  They stressed that the
additional blood was of benefit for any infant born in
any degree of shock following a long labor or difficult
delivery, and helped fill the capillary bed of the
expanding lungs.

McCausland et al. reviewed the research of the
preceding 75 years, beginning with that of Budin
(1876) and Schucking (1877), added some data of
their own, provided a summary of attitudes just before
the midpoint of the twentieth century, and voiced their
own reasons in favor of stripping additional cord blood
into the newborn infant:

    "The fetal circulation is well known to all
    obstetricians up until the delivery of the child.  
    What happens and what should be done between
    the second and third stages of labor has caused
    a great deal of confusion and there is wide
    variance in practice.  The authors believe that as
    soon as the child is delivered there is an
    immediate reduction in the size of the placental
    site, the placenta begins to separate at once, and
    thus placental circulation is disrupted.  Then the
    uterus contracting upon a blood-filled placenta
    forces blood through the umbilical vein into the
    baby...
    ... The umbilical vein remains dilated long after
    the umbilical arteries have ceased to pulsate.  
    The cessation of pulsation of the cord is not the
    criterion as to the proper time for clamping the
    cord.  Instead, when the contracting uterus no
    longer causes pressure in the umbilical vein, that
    would be much better time to sever the cord." [1,
    pp195-6]

What ensures full and healthy transition from placental
to pulmonary respiration remains confusing still, nearly
six decades later.  McCausland et al. stressed the
importance of the capillary bed of the expanding lungs.

Respiration, in the lungs, is an exchange of carbon
dioxide for oxygen.  Bohr et al. (1904) provided
evidence that the hemoglobin molecule receives
oxygen with the release of carbon dioxide [2, 3].  
White (1773) pointed out that the shunts in the heart
cannot be expected to close at the instant of birth [4].  
What triggers closure of the foramen ovale and ductus
arteriosus is still not well understood [5, 6].  However,
there should be no confusion that the capillary bed
surrounding the alveoli must be filled with blood before
the exchange of carbon dioxide for oxygen can begin
in the lungs.

What initiates opening of the alveoli at birth?  Could it
be they first fill with carbon dioxide?  Then exhalation
would precede the first breath.  This is where research
efforts should be focused, not on more randomized-
controlled trials of "delayed clamping" of the umbilical
cord.  On what evidence is the current practice of
clamping the cord within seconds of birth justified?  
Doesn't this need to stop?
References
  1. McCausland AM, Holmes F, Schumann WR. Management of cord and placental blood and
    its effect upon the newborn. California Medicine 1949 Sep;71(3): 190-196.
  2. Bohr C, Hasselbalch K, Krogh A (1904) Ueber einen in biologischer Beziehung wichtigen
    Einfluss, den die Kohlensaurespannung des Blutes auf dessen Sauerstoffbindung ubt.  
    Skandinavishes Archiv fur Physiologie 16:402-412.
  3. Hsia CC.Respiratory function of hemoglobin. N Engl J Med. 1998 Jan 22;338(4):239-47.
  4. White C. A Treatise on the Management of Pregnant and Lying-In Women (1773). Canton,
    MA: Science History Publications, 1987. Available from http://www.shpusa.com/bkindex.html
  5. Aslam F, Shirani J, Haque AA. Patent foramen ovale: assessment, clinical significance and
    therapeutic options. South Med J. 2006 Dec;99(12):1367-72.
  6. MacDonald AA, Fowden AL, Silver M, Ousey J, Rossdale PD. The foramen ovale of the foetal
    and neonatal foal. Equine Vet J. 1988 Jul;20(4):255-60.
  1. McCausland AM et al. (1949)
    Management of cord and
    placental blood and its effect
    upon the newborn.
  2. Bohr C et al. (1904) Ueber
    einen in biologischer
    Beziehung wichtigen Einfluss,
    den die
    Kohlensaurespannung des
    Blutes auf dessen
    Sauerstoffbindung ubt.  
  3. Hsia CC.Respiratory function
    of hemoglobin.
  4. White C. A Treatise on the
    Management of Pregnant and
    Lying-In Women (1773).
  5. Aslam F et al. (2006) Patent
    foramen ovale: assessment,
    clinical significance and
    therapeutic options.
  6. MacDonald AA, et al. (1988)
    The foramen ovale of the foetal
    and neonatal foal.
References
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