In the hospital, a newborn's umbilical cord is cut right after birth. In many birth centers and homebirths, the cord is left intact until it stops pulsing, which is usually about 20 or 30 minutes, around the time the placenta normally delivers. Some parents request even longer delays. What difference does it make to the baby?
The Blood in the Placenta and the Cord Belongs to the Baby
During pregnancy, the placenta, or "afterbirth," filters and oxygenates fetal blood. The process of birth pushes about 66cc of blood back up the cord into the afterbirth. It is believed that this blood engorges the placenta and helps it remain adhered to the uterine wall through changes in contour, such as when the bag of water breaks(1).
Once the baby leaves the mother's pelvis and is squeezed down the birth canal, changing pressure on the vessels in the umbilical cord releases warm, highly oxygenated blood into the baby's circulatory system. The blood fills and dilates capillaries in the newborn's lungs, expanding the aveoli, or air sacs, and making them easier for the baby to fill with the first inhalations. Fluid in the aveoli is forced into the bloodstream as air fills the sacs.
Blood is Redistributed, or Transfused, at Birth
The newborn receives approximately 100cc of blood from the placenta, which occurs within the first four minutes after birth. Besides perfusing the lungs, blood also goes to the intestines and the kidneys, preparing them for digestion and elimination(2).
As the baby begins to breathe and oxygenate his own blood, the arteries in the umbilical cord which carried blood to the placenta slowly begin to close. Each time the mother has a contraction, blood from the placenta is pumped to the baby through the umbilical vein, which is twice as large as the arteries and has no valves. Thus, the baby's body easily maintains the proper amount of blood; any excess can flow back to the placenta. True physiological cord closure occurs in one to three hours after birth(2). If the cord is going to be clamped early, the baby should be kept within four inches above or below the placenta (on the mother's lap if she is sitting up) to get the greatest physiological transfusion in the short time available. When cord clamping and cutting is delayed until the placenta is delivered, it doesn't matter where the baby is placed--anywhere within cord's length (the mother's arms) is fine(3).
Immediate Cord Clamping Causes Shock Conditions
A baby whose umbilical cord is severed at the moment of birth does not receive the bolus of blood from the placenta. Instead of perfusing the gut and other organs, survival dictates that available blood is directed to the heart, lungs, and brain. Loss of needed blood results in some pathological symptoms of shock in the newborn. If the cord is cut before the baby has a chance to take a few breaths, the important transition to extrauterine life may be marred by first breaths that are taken in an overwhelming sense of fear and panic(4).
Erasmus Darwin, grandfather of Charles Darwin, said in 1801: "Another thing very injurious to the child, is the tying and cutting of the navel string too soon; which should always be left till the child has not only repeatedly breathed but till all pulsation in the cord ceases. As otherwise the child is much weaker than it ought to be, a portion of the blood being left in the placenta, which ought to have been in the child."
The timing of umbilical cord clamping and cutting is much shorter in hospital births than it is in births that take place at home or in most birth centers. Babies whose cords are not severed immediately after birth receive oxygenated blood from the placenta while fluid is being displaced from their lungs and vessels in the cord slowly close.
References:
(1)Walsh, SZ, Maternal effects of early and late clamping of the umbilical cord, Lancet, May 11, 1968
(2)Mercer, J, Bewley, S, Could early cord clamping harm neonatal stabilisation, Lancet, May 9, 2009
(3)Dr. Sarah Buckley, Gentle Birth, Gentle Mothering, One Moon Press, 2005
(4)Anne Frye, CPM, Holistic Midwifery: A Comprehensive Textbook for Midwives in Homebirth Practice, Labrys Press, 1998
Mary Earhart - Mary Earhart, RN, BSN, is a Licensed Midwife. She has written articles for professional journals and grants for non-profit agencies as ...
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