To Clamp or not to Clamp... "When?" is the Question

by Michele Brown

midwife clamping cord after a water birthThere are a million and one things to think about before arriving at your medical facility to deliver your baby. You may want to think about your La Maze exercises or if all your favorite songs are on your iPod. But, there is one thing you should think about long before you leave your house with contractions.

Clamping

I believe clamping of the umbilical cord is a conversation all pre-parents should have with their OBGYN early on during pregnancy. I speak about this to my patients because the outcomes of the timing are so important.

Why? Because clamping of the umbilical cord not only has important implications for the newborn infant, but because both mothers and infants can be affected positively or negatively. That's why there is an ongoing debate between doctors and midwives regarding the benefits and risks of the appropriate time to cut and clamp the umbilical cord. This argument generally refers to clamping within the first 15 seconds of life or to delay clamping as long as one to three minutes after birth.

Below is a summary of the literature regarding the pros and cons of immediate vs. delayed clamping of the cord:

Advantages of delaying the clamping of the cord

  1. Reduces the incidence of anemia in the newborn.
  2. Hemoglobin concentrations remain elevated for 2 to 4 months after birth.
  3. Iron stores are increased for at least 6 months after birth.
  4. Fewer infants need blood transfusion.
  5. Studies of very low birth weight infants showed some protection against intraventricular hemorrhage (bleeding into a baby’s brain), late onset infections, and prevention of motor disability especially noted in male infants.

Facts: A delay of even 30 to 45 seconds in cord clamping, especially in preterm infants can provide more blood volume and improve cardiovascular stability. By delaying even 30 seconds, blood volume can increase by 8 to 24% (2–16 ml/kg at cesarean section or 10–28 ml/kg after vaginal birth).

In preterm infants , this can be critical in increasing blood pressure, establishing higher hemoglobin levels which can transport more oxygen to the tissues resulting in fewer days on a ventilator, fewer transfusions, lower rates of intraventricular hemorrhage, fewer cases of necrotizing enterocolitis (death of bowel tissue), and fewer cases of bronchopulmonary dysplasia. (chronic lung disease of newborns).

The theory is that immediately after birth, the infant must increase the heart's output to the lungs dramatically which requires adequate blood volume. If the cord is clamped too soon, not enough volume is present so the body must "borrow" it from other areas of the body such as the brain and the gastrointestinal tract and the lung itself resulting in lower blood flows in these areas with potential damage occurring.

This damage can result in increased morbidity, mortality, and developmental delays. By delaying the clamping of the cord, the additional amounts of blood can stabilize blood flow to the brain and these vulnerable tissues, and increase the oxygen supply preventing infections and damage to these organs.

Disadvantages of delayed clamping of the cord?

  1. Polycythemia—hyperviscosity (large increase in packed red cell volume which can result blood clots or possibly stroke)
  2. Higher peak bilirubin concentrations requiring possible treatment with phototherapy
  3. Increased risk of maternal blood loss while waiting for clamping of the cord.
  4. Possible delay in resuscitation of the infant if needed (less than 10% of infants need resuscitation) causing respiratory distress.

Facts: Studies have shown that although babies can have more packed blood volume from the delay in clamping of the cord, no adverse consequences have resulted from this. In addition, none of the infants studied had any increased risks of respiratory distress, or increased need for intensive care or length of hospital stay. Some infants had an increase in serum bilirubin causing jaundice requiring phototherapy at birth. There was no increased risk of maternal bleeding by delaying the clamping of the cord.

How is blood volume in the infant changed by the delay and position of the newborn after birth?

The total fetoplacental blood volume is about 120 ml/kg of fetal weight. The distribution of blood between the fetus and the placenta is 2 to 1 which remains the same if the cord is clamped immediately. Delayed cord clamping can result in an extra 20 to 40 ml of blood per kilogram of body weight to the fetus which is also an extra 30 to 35 mg of iron.

By delaying 3 minutes, these higher infant blood volumes are obtained, especially if the infant is held about 10 cm below the level of the placenta. By holding the infant even lower, at about 40 cm, the placenta hastens blood transfusion to the infant to within one minute. Without lowering the infant, placental transfer of blood may fail to occur.

Summary

Full Term Infants
Delayed clamping in the cord of full term infants is safe. Waiting for at least a minute, but preferably 3 minutes, before clamping the umbilical cord reduced the risk of neonatal anemia without incurring any major side effects in the newborn or the mother. Positioning of the baby should be on the mothers abdomen or lower. In poorer countries, where fetal anemia is common and often associated with higher mortality with impaired mental and motor development, delay in clamping of the cord can serve as a simple and very effective means of improving infant survival.

Oxytocin can still be administered after delivery to reduce maternal blood loss while waiting the three minutes for cord clamping. Use of oxytocin can also enhance placentofetal transfusion.

Premature Infants
For premature infants, even a delay of 60 seconds with the infant lowered, can be critically important. Studies found no impact on risk of polycythemia, respiratory distress in the newborn, serum concentration of bilirubin, need for intensive care, length of hospital stay, or infants weight when clamping was delayed.

Clamping the cord too soon can result in decreased blood volume in premature infants which can result in poor blood flow with reduction of oxygen delivery to parts of the premature brain resulting in enhanced possibility of motor damage and developmental delays. Also, the risks of postpartum hemorrhage (blood loss of 500 cc) was no different from delayed vs immediate cord clamping.

Dr. Brown, founder of Beauté de Maman, is a board-certified member of the American College of Obstetrics and Gynecology, a member of the American Medical Association, the Fairfield County Medical Association, Yale Obstetrical and Gynecological Society and the Women's Medical Association of Fairfield County. She is a magna cum laude graduate of Tufts University, completed her medical training at George Washington University Medical Center and completed her internship and residency in obstetrics and gynecology at Yale-New Haven Hospital. Dr. Brown has a busy obstetrical practice in Stamford, Connecticut and, as a clinical attending, actively teaches residents from Stamford Hospital and medical students from Columbia Presbyterian Hospital in New York.

Copyright © Michele Brown. Permission to republish granted to Pregnancy.org, LLC.