Benefits of Delayed Cord Clamping

What is delayed cord clamping and why is it important?

Sara Church, CNM

When most people think about the birth of a baby cutting the umbilical cord is one of those archetypal images we hold in our minds. That moment when the cord is cut by the partner and mom and baby are physically separated for the first time. What we don’t often think about are the implications of the timing of umbilical cord clamping and cutting.

But we should think about that. When the cord is clamped and cut, mom and baby are physically separated for the first time! The timing has implications for immediate adaptation and transition for that baby, future iron stores for that infant (think brain and muscle development!), infusion of stem cells (we don’t really know the full implications of that yet!), and mother/infant bonding.

At the time of birth, approximately 1/3 of the blood supply for the baby is located in the placenta. If the cord is clamped and cut immediately (immediate cord clamping), that blood and all the good stuff it carries is forever lost to that baby. As the baby begins to breath and cry, the lungs open up and the change blood pressure in the baby encourages one-way flow from the placenta to the baby. As the oxygen saturation levels in the baby increase, the umbilical arteries close and blood continues to flow from the umbilical vein to the baby (after about 45 seconds). Our babies and placentas have evolved to allow this profusion from the placenta to baby, and there are many who argue that “delayed” cord clamping, now defined as waiting anywhere from 60 seconds after birth until after the birth of the placenta, is actually “physiologic” cord clamping.

If the umbilical cord is left intact from between 2-5 minutes the result is a 40% increase in blood volume, 45% increase in hematocrit, 50% increase in total red cell blood cell volume and 50% of this change happens within the first 60 seconds.

So, what does this mean for the baby? Immediately, that blood is still being oxygenated by mom, so baby has some extra support while those lungs start to work full force. The extra blood volume helps to profuse the lungs, liver, and kidneys. Delayed cord clamping has been found to improve resuscitation efforts in compromised babies, and institutions are now beginning to include delayed cord clamping in their policies for babies who need resuscitation and trying to make changes that bring the resuscitation to the bedside to keep the cord intact longer. 

Longer term studies have demonstrated a significant increase in newborn hemoglobin levels and significantly higher ferritin levels in infants even up to 6 months of age. This is important because iron is necessary for neurologic development and breastmilk is not a high source of iron. In addition, delayed cord clamping allows transfusion of high concentrations of fetal stem cells, which may play a role in further development of the child.

Are there any risks to delayed cord clamping? The most commonly cited is a statistically significant number of newborns with jaundice requiring phototherapy (3% of immediate cord clamping vs 5% of delayed cord clamping), but no difference in sick babies or long-term outcomes. There was no difference found in the studies regarding postpartum hemorrhage or delay in delivery of the placenta. There was no difference in Apgar scores or NICU admissions.

About those stem cells, what if you are planning Private Cord Blood Banking? Most of the commercial cord blood banks now include information in their literature regarding delayed cord clamping and stem cell collection. A study by the NY Blood Center demonstrated that collection volume and cells counts were significantly decreased if clamping was delayed more than 60 seconds, and 46% of those collections didn’t meet the minimum volume criteria. The cord blood banks typically recommend delayed cord clamping “up to 60 seconds”. Additionally, tissue storage, collection of the actual umbilical cord, is unaffected by timing of cord clamping and cutting.

The last argument I would use in favor of delayed clamping is protecting that mother baby unit from outside interruption and intervention. As long as baby is attached there is no weighing, diapering, or separation from that crucial skin-to-skin contact going on! If hospital staff wants to take the baby, we just shrug our shoulders and say with a smile, “Sorry, still attached!”


Sara Church, CNM was born at Norwalk Hospital and has been joyfully practicing full-scope midwifery there since 2009. She obtained a BS in Diagnostic Genetics at UCONN before following her calling as a midwife. She obtained her BSN and MSN in Midwifery at Columbia University. She is adjunct clinical faculty with Yale Midwifery school and precepts midwifery students from Yale, Columbia, and Frontier. In addition, she serves as co-secretary on the board of the CT Affiliate of the American College of Nurse-Midwives and is a member of the Government Affairs Committee for the American College of Nurse-Midwives. In her spare time she is the proud mom of two boys who juggles fart jokes and good manners.