Delayed Cord Clamping Part One: A Look at the Evidence

Let's start this with: I have a new favorite blog.  I might not love every post and I definitely haven't read every post from the archives.  But when it comes to a research-based look at obstetrical procedures, I'm finding this blog far more favorable than not - The Academic OB/GYN, blogger Dr. Nicholas Fogelson.  His articles are intended for obstetricians, not for the average person delving into the world of obstetrics for such minor things as having a baby (now I hope you all caught the complete sarcasm there) but his posts are actually research-based and not always in line with ACOG and AAP (which is something I've come to admire as I've learned more about the constraints of the system).  Tonight's post is inspired by and largely based on his Grand Rounds discussion from January 2011, at the University of South Carolina School of Medicine (but I promise it will read much more easily than that sounds).

More times than I can count, I've had couples in classes ask "What about delayed cord clamping?"  Such a valuable question.  What about it?  

Delayed cord clamping refers to waiting, an undetermined amount of time, to clamp and cut the baby's umbilical cord after birth.  Fogelson has compared the modern procedure of immediate cord clamping and cutting to the antiquated practice of blood-letting, "It's interesting to talk about blood-letting and then talk about immediate cord clamping because I think that you'll see a bit of a parallel."  Perhaps one of his most poignant and beautiful points is made in watching the role that cord clamping takes on in births outside of the human realm.  The clips Fogelson shows from the births of a cat, a horse, an orangutan, and a dolphin show nothing being done to the cord.  That is, the cord is actually simply ignored by the mother for a long while after the birth.  The cat and orangutan take their time licking their little ones while the foal figures out it's way onto it's feet.  The dolphin in Fogelson's video starts moving it's tail and swims up and with it's mother.  It is only in human culture that we've initiated this obsession with cord management.

Cultures around the world have varying traditions surrounding the umbilical cord.  In some cultures, a lotus birth is the tradition, where the placenta is left attached to the baby until the cord naturally falls off on it's own (usually a few days shorter than when a "cord stump" dries up and falls off).  In other cultures, the midwife calls in another woman from the community to cut the cord.  In the islands of Micronesia, the cord is referred to as "the house of the soul" and is preserved in a small box or burred with the placenta near the family's home (Kitzinger, 145).  One thing that remains constant, though, is that the need to 'care for' the cord seems to be a distinctly human trait.

The umbilical cord is composed of three vessels.  Two vessels (arteries) bring waste products away from the baby back to the placenta and one vessel (vein) brings blood and nourishment to the baby.  Until the placenta begins to detach from the mother's uterus, the cord  has the potential to continue bringing blood and nourishment to the baby.  This means that human umbilical cords will often pulsate for at least ten minutes after birth.  In addition, as the cord is exposed to the air, it begins to contract but the first vessels that are closed off are those that bring waste products away from the baby, meaning the vessel bringing blood to the baby continues to pulsate and closes off last. It's theorized that this allows the baby a certain measure of circumstantial control over it's use of this extra blood volume (Buckley).  Interestingly, a placenta drained of blood tends to shear away from the lining of the uterus more easily than a placenta swollen with blood (Kitzinger, 145).  

I have had several clients whose OB told them that the baby must be held below the mother after birth for gravity to allow the benefits of cord pulsation.  Some research does show that holding the baby at or below the level of the uterus until cord pulsation ceases maximizes the blood transfer.  In considering this, I remind mommas that birth and the immediate postpartum is a complexity of physiological and emotional responses to the baby's entrance into the world.  Having the baby on one's chest while the cord pulsates may not lead to maximum blood transfer from the placenta but will provide the baby with a portion of it's own blood while also providing the benefits of immediate skin to skin contact with mom.  According to the World Health Organization, "Trials in which newborns were placed on the mother's abdomen or on the bed where she lay and the cord was clamped only when it stopped pulsating showed that these babies had blood volumes 32% higher than babies whose cords were clamped immediately after birth" ("Review of Evidence").  Thirty two percent higher blood volume paired with skin-to-skin benefits such as lower cortisol levels, assistance in regulating breathing, heart rate, and temperature, elevated blood sugar levels, and colonization of the mother's bacteria ("The Importance of Skin-to-Skin"), to name a few, is a far better deal for most babies than 50% greater blood volume from being held below the level of the mother's uterus and being denied skin to skin with mom.

The clinical indication for keeping the baby at uterus level while the cord is intact really comes into play in the case of a cesarean.  After a cesarean, babies are often held at a level several inches higher than the uterus.  In this case, gravity can force the blood to remain in the placenta.  According to Sarah Buckley, MD, this may cause an increased incidence of respiratory distress in babies born via c-section; several studies have shown respiratory distress can be eliminated in many circumstances by allowing a full transfusion of blood from the placenta.

By delaying the clamping of the umbilical cord, babies gain up to 40% of their own blood volume (Fogelson) and increase their oxygen level (Buckley).  This cord and placental blood provides a back-up of blood for use in the rapidly changing pulmonary and organ systems (such as the lungs).  When the cord is clamped immediately, other organs sacrifice their blood to the pulmonary system since it requires blood immediately for necessary lung function when the blood-oxygen supply from the placenta is cut off (Morley).  Studies have found delaying the clamping of the cord helps raise iron levels, reducing the risk of anemia, in addition to favoring early contact between mom and baby (WHO, "Delayed Clamping").  A frequent question I hear is about the potential for greater jaundice levels due to the increased blood volume.  Research does show that jaundice levels can be higher when the cord is clamped later versus earlier with no adverse effects (Morley) and actual antioxidant benefits from the bilirubin (MIreles).

The research that our technology and advances in science and medicine allow us is crucial in aiding our understanding of physiological processes.  As professionals, though, information that challenges the accepted norm can be difficult to recognize.  As Fogelson noted in his Grand Rounds, it may be comforting for those whom have trouble incorporating new technique into their practice to realize that delayed cord clamping has, in fact, a fairly strong history.  Even Erasmus Darwin, grandfather of Charles Darwin, in 1801 recognized the importance of blood flow to the baby:
"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 part of the blood being left in the placenta which ought to have been in the child."

Stay tuned for a later post offering up some suggestions as to how you can use this info in your birth, where to go from here, and how to have conversations about topics like these with your care provider.

Sources
Buckley, Sarah J. "A Natural Approach to the Third Stage of Labour." Midwifery Today Autumn 2001: 33-36. Print.

"Delayed Clamping of the Umbilical Cord to Reduce Infant Anaemia."  WHO.  n.p. 2014. Web. 5 Oct. 2014.

Fogelson, Nicholas. "Delayed Cord Clamping Grand Rounds Part 1. Online Video Clip. YouTube. YouTube, 30 Jan. 2011. Web. 4 Oct. 2014.

"The Importance of Skin to Skin Contact." International Breastfeeding Centre. ibc, 2009. Web. 6 Oct. 2014.

Kinmond, S, T C Aitchison, B M Holland, J G Jones, T L Turner, C A J Wardrop. "Umbilical cord clamping and preterm infants: a randomised trial."  BMJ Volume 306 16 Jan 1993: 172-175. National Center for Biotechnical Information. Web. 5 Oct. 2014.

Kitzinger, Sheila.  Rediscovering Birth. New York: Simon & Schuster, Inc., 2000.  Print.

MIreles, L C, M A Lum, P A Dennery.  "Antioxidant and cytotoxic effects of bilirubin on neonatal erythrocytes." Pediatric Research 45(3) (Mar. 1999): 355-62. Web. 6 Oct 2014.

Morley, G M. "Cord Closure: Can Hasty Clamping Injure the Newborn?" OBG Management July 1998: 29-36. Print.

"Review of Evidence on Cord Care Practices."  WHO.  n.p. n.d. Web.