[back] Cord Clamping
Delayed Cord Clamping
by Hilary Butler.
Mothering, No 41, Fall 1986, pages 73 - 76
Expulsion of the Placenta.
The Effects of Cord Clamping on the baby.
Cord Clamping and Hyperbilirubinemia
Literature describing the consequences of early clamping of the umbilical
cord is scant. The ramifications of this routine procedure are, however,
potentially serious. The majority of cultures, when left to their own
traditional birthing practices, retain an appreciation for the way nature
has equipped a woman's body to deal with placental deliver. In South
Africa, for example, the Bantu people will not touch the cord until the
placenta is expelled. 1 On the other hand,
among cultures which have taken up active management
of the third stage of labour much of this appreciation
has been lose.
In 1737, Monsieur François Mauriceau published a manual advising that the cord be immediately knotted and cut, and recommended that the "patient" be subsequently relieved of the placenta - for fear that the uterus might close - by turning the cord two or three times around the left hand, pushing the fingers of the right hand into the vagina to keep the uterus up, and pulling the placenta out. 2 Although practitioners in the maternity field today do not go to such extremes, they have been trained to believe that cutting the cord before delivering the placenta benefits the baby. Evidence to the contrary begs us to take a new look at this practice.
Expulsion of the Placenta.
The function of uterine contractions in the third stage of labour is to separate the placenta from the wall of the uterus, expel it, and control haemorrhage. 3 This is effected by contraction and retraction.
At deliver there is already micro-separation of the placenta due to the retraction that has taken place during pushing. While the surface of the uterine wall to which the placenta adheres does shrink, the placenta itself cannot reduce it surface area, and so it separates from the uterine wall. This process can be illustrated by sticking a postage stamp to a piece of stretched elastic. When the elastic shrinks (contracts), the postage stamp peels off (retracts). As the uterus contracts downwards from "chest to vagina", the placenta is forced in the direction of least resistance -toward the vagina. If the cord has not been clamped, this process if rapid and the placenta is expelled without resistance into the vagina. If the mother is squatting, it will be "delivered" by gravity.
The blood supplying the placenta runs within blood vessels, or "sinuses", which develop between groups of crisscrossing muscles during placental maturation. These sinuses close as the uterine wall contracts, and the blood vessels supplying the placenta are thus shut off. When the cord is left unclamped, pressure from uterine contractions maintains continuous blood flow from the uterus and placenta so that the blood going to the baby continues to be saturated with oxygen. Even as the placenta continues to function, its decreased blood volume causes it to shrink, separating quickly and easily, as the uterus rapidly closes off the blood vessels. (in the event that these blood vessels do not close off, care must be taken to treat maternal bleeding by removing the placenta - but not necessarily cutting the cord.)
When the cord is clamped before the placenta is delivered, however, the counter resistance from the un-shrunken placenta can be great enough to impede complete retraction. Separation and expulsion, are thereby impaired by the bulky and blood-laden placenta. A retained placenta prevents uterine muscles from closing off the blood vessels, and increases the risk of maternal blood loss. Studies have shown that immediate cord clamping prolongs the average duration of the third stage, and greatly
increases maternal blood loss. 4
Retraction of the placenta, which quicken separation and expulsion and reduces blood loss, can only be achieved naturally, by allowing the cord to remain unclamped - or, in cases where the cord must be cut, by leaving the placental end unclamped. Maintaining this continuous blood flow to the baby reduces placental blood volume, and therefore reduces uterine contents by approximately 90 mls of blood. As retraction occurs, contraction of the uterus squeezes more blood out of the placenta, further reducing its size and supplying the baby with this blood.
For mothers who are Rh-negative, this is especially important. Fewer Rh-negative mothers of Rh-positive babies develop antibodies when the cord is unclamped and separation of the placenta is spontaneous. 5 Normally, the placental barrier prevents mixing of maternal and foetal circulation. However, when the placenta separates after cord clamping, the baby's blood, which is still in the placenta, can mix with the mother's blood, causing maternal contamination.
The Effects of Cord Clamping on the baby.
Before birth, a baby's blood is distributed throughout his or her placenta
and body. The blood in the baby and in the placenta rightfully belongs to
the baby and should go with him or her at birth. Many health practitioners
mistakenly think that the baby's body is already full of blood and that the
placental blood is excess. The placental blood, however, serves and
Prior to birth, the baby's lung alveoli are fluid-filled, and as such they
keep the blood vessels of the lungs constricted, automatically impeding the
flow of blood to the lungs. When a baby is passing through the birth
canal, the pressure exerted all around his body forces the fluid up and out
of his lungs so that by the time he is born, the major portion of his lungs
is clear of fluid. At birth the blood vessels of the lungs fill with blood
and, within seconds, the baby starts to breathe. This increased need for
pulmo0nary blood flow to breathe, combined with the increased movement of
the baby's arms and legs, provides ample use for the placental blood.
When the cord is clamped immediately, the baby attempts to breath right
away, without the aid of the oxygenated blood from the placenta. For
premature babies, this can be particularly consequential. Several American
reports suggest a tendency among hospital-born babies whose cords are
immediately clamped to have poor circulation and bluish limbs. Could it be
that they have simply not received their full quota of blood from the
placenta? Could the reduced portion of blood volume available have gone
toward the maintenance of major heart, lung, brain, and digestive functions
at the expense of the circulatory system?
If a blood pressure gauge is placed on an unclamped umbilical cord, it
will pick up pressure rises as high as 60 mm Hg (millimetres of mercury)
with each uterine contraction. This indicates that these contractions are
intimately involved in the transfer of placental blood through the cord. A
striking pressure rise, which persists through the first few hours of life,
is also evident in the baby's vena cava and right atrium of the heart. 6
All studies on this indicate a significantly higher systemic pressure in
infants who have been clamped late (90 percent in the first nine hours),
and conversely a significant drop in pressure in early clamped infants (70
percent of systemic by the second hour, and almost 50 percent of systemic
by the fourth hour).
Furthermore, three groups of researchers have independently reported that
early clamped infants have a much higher incidence of cardiac murmurs
during the first 14 days of life. 7 Granted, under certain circumstances,
a baby's cord must be clamped immediately for instance, when it is wrapped
too tightly around the nick. However, under ordinary circumstances it
appears that an early clamped infant may not be operating at full potential.
While several researchers have documented the effects of early clamping on
the baby's circulatory system, no one has studied the possibility of damage
to the baby who has less oxygen-carrying capacity due to a reduction in
Following are some of the published statistics, well documented in
numerous studies, relating to the quantity of blood and the percentage of
red blood cells in the cord and placenta.
· A baby's optimum blood vo9lume is calculated at 85 mls per kg of body
· In full-term infants, placental transfusion increases the blood volume of
the newborn baby by 40 - 60 percent. Such infants retain a 50 percent
larger red-cell volume dispersed through a slightly enlarged blood volume,
with higher hematocrit values than are found in infants whose umbilical
cords are clamped immediately at birth. 9
Other studies show:
· The placental blood normally belongs to the infant, and his or her
failure to get this blood is equivalent to submitting the newborn to a
severe hemorrhage at birth. 10
· Deprivation of placental blood results in a relatively large loss of iron
to the infant. 11
· The time of cord clamping may be involved in the pathogenesis of
idiopathic respiratory distress syndrome (the earlier clamped, the more
respiratory distress). 12
· Placental blood acts as a source of nourishment that protects infants
against the breakdown of body protein. 13
In essence, an infant who has had the cord clamped immediately has been
subjected to the equivalent of a severe haemorrhage, deprived of a
significant percentage of his or her blood volume and red cells, robbed of
his or her rightful store of iron, placed at risk of some respiratory
distress, and denied protection against the breakdown of body protein. Is
this baby in optimum condition?
Cord Clamping and Hyperbilirubinemia
"If delayed cord clamping is adopted as a means to reduce the incidence of
respiratory distress syndrome in premature births, there will be an
accompanying augmentation of hyperbilirubinemia (jaundice) to deal with."
14 This increased incidence of jaundice among premature infants has been
used as a primary argument against delayed cord clamping in full-term
infants as well.
Low levels of bilirubin are part of the normal physiologic process in the
newborn. At birth, the liver constitutes approximately 4 percent of the
body weight and occupies a considerably larger portion of the abdominal
cavity than it does later in life. It is the primary organ involved in
bilirubin metabolism, 75 percent of which is derived from red blood cells.
The iro9n produced by the breakdown of red blood cells is concentrated in
the liver for release during the first year of life. The by-product of
this breakdown, bilirubin, is what causes the characteristic yellowing of
the skin seen with hyperbilirubinemia.
Whereas physiological jaundice is a naturally occurring process, non physiological jaundice requires special consideration and neonatal help. 15 Factors contributing to non physiological jaundice include premature birth and medications that have passed through the placenta during (and prior to) labour. Among other drugs, Pitocin inductions and epidural anaesthetics have been conclusively linked with non physiological neonatal jaundice. 16 Actually, any drug administered to mother or baby must be viewed with a "jaundiced" eye, for it is likely to compete with bilirubin sites on blood protein, causing more bilirubin to be free to contribute to jaundice.
In an all-out effort to prevent the possibility of jaundice, obstetric practitioners have reasoned against delayed cord clamping, since it increases the volume of red blood cells, which, in breaking down, will produce increased levels of bilirubin. To prohibit the flow of this "excess" blood, obstetricians routinely intervene and clamp the cord immediately following birth. True, hyperbilirubinemia might be prevented in premature and "medicated' infants by early clamping; however, in a normal delivery of a full-term, un-medicated infant, there are untold advantages to delayed cord clamping until after the placenta has delivered itself.
This article appeared in another form in the New Zealand Association of Midwives Newsletter.
1. Both (See Bibiography).
2. Mauriceau: 189
3. Donald: 292, 564.
5. Doolittle and Moritz.
6. Moss et al.
7. Buckel, Arcilla, Burnard, and James.
9. Saigat et al.
10. De Marsh et al.
11. 11 De Marsh et al.
12. Saigat et al.
13. De Marsh et al.
14. Seigat et al.
15. For information on the management of jaundice, see "Phototherapy", by
Mary Ban Recla, in Mothering #29, and "Jaundice and Breastfeeding" by
Lawrence M. Gartner and Kathleen Auerback in this issue.
16. Swartz, Chalmers, and D'Souza.
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Swartz, James F. "Drug Induced Neurological Disorders in Childhood."
Current Problems in Pediatrics 1 : 12 (October 1971): 1 - 57.
Walsh, S. Zoe. "Maternal Effects of early and Late Calmping of the
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Hilary Butler (31) is a consumer advocate for birthing women and
alternative health in New Zealand. She has two children: Ian (4) and
David (2). Her family also includes her husband Peter and his three
children: Kirsten (26), Mark (25) and Michael (23). Hilary and her family
are involved in Christian home education in New Zealand.