July 2004
1
Hypothesis: Clamping the Umbilical Cord may be
Unsafe
Placental blood is respiratory blood – to be transferred to the lungs, not discarded or banked for future use
Placental blood is respiratory blood – to be transferred to the lungs, not discarded or banked for future use
A proposed factor for
consideration in retrospective
and prospective outcome studies
by the Pregnancy and Infant Working
Group of the National Children's
Study (NCS)
Eileen Nicole Simon, PhD, RN
1. Placental blood is respiratory blood
Circulation and an adequate
volume blood are essential for
respiration. The fetal heart is the earliest organ to become functional, and between the fourth and fifth weeks of development begins circulating erythrocytes produced in the embryonic yolk sac [1]. The
placenta becomes a major component
of the cardiovascular system between
the eighth and tenth weeks [1, 2]. Blood is pumped by the fetal heart through the umbilical arteries to the placenta, where
replenished with oxygen and
nutrients it returns via
the umbilical vein [2, 3]. Placental blood
is therefore part of the fetal circulatory system, as much as pulmonary blood is after birth.
Erasmus Darwin in 1801 noted,
"The placenta is an organ
for the purpose of giving due
oxygenation to the blood of the fetus;
which is more necessary, or at least more
frequently necessary, than even the supply
of food" [4, p192]. Oxygen is the most urgently essential ongoing need of all species dependent for survival upon aerobic metabolism.
Research by Redmond et al. in 1965
provided dramatic evidence that the
infant's first breath redirects
blood from the placenta to
the lungs [5]. This so-called
"placental transfusion"
fills the capillaries surrounding the
alveoli, causing them to open [6]. Placental blood is respiratory blood, and appears by nature's design intended for perfusion of the lungs at birth [7].