[back] Cord Clamping
Journalist's Dissent to Clamping. Potential Dangers of Childbirth Interventions
"Early clamping of the umbilical cord: Cutting the ties that bind"
by Cory Mermer
Townsend Letters, April 2000 Issue #201, p 74-
Most likely the first medical intervention to which every infant is subjected to is the clamping of his or her umbilical cord. Under normal circumstances, in most of western society, this is done almost immediately, without the matter even being given a thought and often before the infant has taken its first breath. A vast majority of parents, and possibly many doctors and midwives as well, are completely unaware or at least unfamiliar with the controversy surrounding this issue. This is quite astounding when you realize that disagreement and debate has surrounded this practice for a long time, dating back at least 200 years and probably much longer 1.
The immediate clamping and cutting of the umbilical cord is a common practice that deprives the newborn of a substantial amount of possibly its most valuable possession: placental blood with all of its oxygen-carrying capacity, vital nutrients and immune enhancing antibodies. The purpose of this paper is to further explore the issue and the still-ongoing debate.
Active vs. Expectant Management of the 3rd Stage of Labor Cord clamping is part of the "third stage" of labor, which begins after the baby is delivered. The two primary approaches to the third stage are often referred to as "active" and "expectant" management. One of the primary reasons for the medical establishment's favoring early clamping is their overwhelming preference for "active" management. This preference is due to a belief that it is safer for the mother. Early clamping (EC) would most likely occur in an "actively managed" 3rd stage, since oxytocin administration and controlled cord traction are the norm, thereby precluding late clamping (LC) 2.
However, although "active" management of the 3rd stage has been shown to reduce maternal blood loss, it does not necessarily result in a decrease in maternal mortality or seem to have any obvious long-term effects on the mother 3. The long-term effects of this practice on the newborn, on the other hand, have not been adequately investigated 4. The modest maternal blood losses found are not surprising or alarming since, in healthy women, postpartum blood losses of up to 1000ml may still be considered physiological and do not necessitate treatment other than oxytocics 2.
Advantages Most of the reasons for the possible advantages of LC (see Figure 1) can be explained by two vital elements: Oxygen and Iron. However, since the main function of iron in the body is facilitating the transport of oxygen, we can even reduce this further to simply say that improved oxygenation is responsible for most of the purported and potential benefits.
Additional Blood Volume Although the debate over the benefits and risks of early clamping vs. late clamping continues, it has become a fairly well-established fact that the newborn does receive a substantial amount of extra blood, referred to as placental transfusion, when clamping is delayed. It is not so much the existence of such a phenomena that is debated, but rather the significance and value of the additional blood.
It has been asserted that placental transfusion helps to prevent hypovolemia, a condition of decreased blood volume, normally resulting from blood loss or dehydration 21,30. Estimates on the additional quantity of placental transfusion with LC vary, depending on several factors (see Figure 2), from 10 to 60 ml of blood per kg of body weight 5-13,30,48,51. The estimated additional blood volume varies from 20% to 60% of the existing supply 11,15,16.
This is a significant enough quantity for immediate cord clamping to be referred to as "the equivalent of subjecting an infant to a massive hemorrhage" 14. Not exactly the way one would hope to welcome a new life into the world. The estimated average total blood volume of term infants has been reported to be between 80 and 90 ml/kg 19, 20 or a total volume of 310 ml 52.
The birth position assumed by the mother has as great impact on the quantity of placental transfusion. Taking full advantage of gravity, this transfusion is greatly facilitated when the squatting birth position is practiced, as is still commonly done throughout the less developed nations of the world, as well as by our closest evolutionary relatives, the primates 14.
Another study estimated that about 35 ml of blood per kg of birth weight is transfused when infants are kept at the level of the vaginal opening and the cord is clamped 3 minutes after birth 17. The same authors later found a 32% higher blood volume in babies who were placed on their mother's abdomen and the cord clamped after it stopped pulsating 18. This practice has become more common in the "natural childbirth" setting, but still only takes place in a small percentage of overall births.
In a recent report, the World Health Organization (WHO) cited several medical references to back-up it's statement that if the newborn is placed at or below the level of the vulva for 3 minutes before clamping, an approximately 80 ml blood transfer would result 2, 25, 26, 27.
A 1998 study from Great Britain found that LC babies weighed over 2 oz. more than did babies whose cords were immediately cut 3. Following the study, one of the authors stated that they plan on performing follow-up studies on the children when they are between 2 and 5 years of age to attempt to find any impact on the children 4. As we will soon discuss, the possible effects on the infant could be dramatic.
Anemia and Iron status LC has been shown to reduce the incidence of iron deficiency anemia and result in increased hemoglobin and hematocrit levels 5, 7, 17, 19, 28, 38, 48. The trend toward higher hematocrit levels in LC infants were found to be greater in infants born by C-section and those born very premature (26-29 weeks) 42. Even as long ago as 1877, it was shown that LC resulted in increased erythrocyte concentrations 7.
LC has been estimated to provide about 50 mg of additional iron to the infant 2, 39. According to one researcher 16: . a moderate transfusion of about 20-30 ml/kg endows about 30-50 mg of "extra" iron and can help prevent or delay depletion of iron stores during late infancy..placental transfusion could represent a physiological and inexpensive means of increasing iron stores.
The iron status of LC infants has been shown to remain high, even at two months 28 and nine months of age 39. Adequate iron stores are crucial for proper neurological development. Although iron supplements can reverse anemia, impaired cognitive function has still been observed 4 to 5 years later 40. In addition, iron deficiency is often not discovered for several years, at which time there may be irreparable damage, which may even be so subtle as not to be noticed.
Another study found an inverse relationship between the volume of blood remaining in the placenta with the hemoglobin concentration of the newborn 38. Obviously, the less blood remaining in the placenta, the more retained by the newborn. The hemoglobin concentration at birth is of critical importance as it is a measure of the infant's available iron stores 19.
Iron deficiency may be a much more common dilemma than is generally thought. A 1995 diet and nutrition survey from Great Britain showed that 25% of children were iron deficient and 12% had iron deficiency anemia 41.
Could LC improve the iron status and thereby the developmental potential of children throughout the world?
Premature infants Delayed cord clamping has been shown to be especially beneficial with preterm infants by improving outcomes including reductions in respiratory distress syndrome (RDS) 5,10,22,30, blood transfusions 21,30, and ischemic organ damage 30. These benefits are most likely due to the greater erythrocyte volume and oxygen carrying capacity due to the greater blood volume. However, doesn't it make sense that a practice that is better for preterms would be better for full-terms as well? Even though a normal infant may not be at high risk for RDS, wouldn't it still be advantageous to have a greater oxygen carrying capacity? Besides premature infants, the benefits of LC may be especially great for other infants considered to at high-risk for RDS (see Figure 3) 31.
In addition, the lower blood volume with EC may result in a shunting of blood to the infant's more critical organs (e.g., heart and brain), at the expense of others. This may cause complications by rendering some organs ischemic 30. One reason that LC has been shown to be especially beneficial for premature infants is the proportionally greater blood supply gained. With a full-term infant, two-thirds of the blood in the placental-fetal circulation is in the fetal circulation. However, at 30 weeks gestation, only half the blood is in the fetal circulation 44. Therefore, the premature infant is in a more dire hematological position and has more to gain from the greater blood supply provided by LC.
A recently published editorial in The Lancet states that, although there have been many technical advances in the treatment of premature infants, "simple measures that improve outcome, such as late clamping of the cord, seem to have been forgotten" 43. It should not be surprising that conventional medicine is so quick to use high-tech gadgets and pharmaceuticals without first considering simple, natural, and low-cost measures.
Brain Damage and Asphyxia A significant number of infants suffer permanent brain damage during the birth process, often without parents or doctors even realizing it has occurred. Years ago, a report by the National Institute of Child Health and Human Development estimated the number of such cases to be so great as to exceed "the combined annual number of deaths from all types of cancer, the number of deaths in automobile accidents each year, and the total loss of American life in the war effort in Vietnam" 45. Admittedly, it is quite possible that this number has gone down significantly in the years since these comments were published. However, it is probably still not a rare occurrence and may have even gone up.
One researcher, Dr. Abraham Towbin, in the Journal of the American Medical Association, maintained that oxygen deprivation causing minimal brain damage is a common occurrence that is not generally realized. While severe and obvious brain damage and even death can occur after a relatively long period of oxygen deprivation, shorter periods can cause lesser damage, which may go unnoticed until later in life where it can manifest itself as a learning difficulty or behavioral problem 46.
He made the following extremely disturbing observation 46: With the brain marred at birth, the potential of performance may be reduced from that of a genius to that of a plain child, or less. The damage may be slight, imperceptible clinically, or it may spell the difference between brothers, one a dexterous athlete and the other 'an awkward child'.
Dr. William Windle, a former research director at The Institute of Rehabilitative Medicine at the New York Medical Center, made the assertion that any infant that has asphyxia long enough to require resuscitation at birth will almost certainly have brain damage as a result. The number of people with minimal brain damage, in his opinion, is much larger than is widely thought. Citing experiments performed on monkeys in two National Institutes of Health laboratories, he asserted that even infants who seem to recover fully will most likely have permanent brain lesions that may cause subtle deficiencies in memory or behavior 14.
LC could play a crucial role in reducing the number of infants damaged due to asphyxia. One of the main reasons for this is very simple to understand. Infants survive for their entire life, prior to being born, by obtaining oxygen, through the placenta, from the maternal blood supply. When the umbilical cord is clamped, the infants must then rely completely on their own respiratory efforts. However, sometimes infants do not begin to breathe promptly following birth. If the cord has already been clamped, the infant will have no oxygen supply. If left alone, the cord will most likely supply oxygenated blood for several minutes, until pulsation ceases, thereby reducing or eliminating the time that the infant is oxygen deprived.
Early minimal brain damage may also manifest itself later in life as a mental disorder such as schizophrenia. A just published 1999 case-controlled study found that adverse conditions in the womb, such as placental insufficiency, may be a risk factor for early-onset schizophrenia, possibly due to oxygen deprivation 47. If oxygen deprivation to the fetus can result in schizophrenia, it is not so far-fetched to hypothesize that oxygen deprivation, caused by EC, to the newborn may do the same.
Is it possible for LC to permanently improve brain function by providing a greater oxygen supply? Could the rates of disorders such as Cerebral Palsy, mental retardation, autism, schizophrenia and others be reduced? Can LC increase intelligence? None of these questions have yet to be properly addressed, let alone answered.
Immune System Boost It is well established that the newborn receives a plethora of maternal antibodies from the placental blood supply. Therefore, it stands to reason that by increasing this supply, you are increasing the quantity of these immune-enhancing antibodies as well. Considering the fact that these antibodies continue to provide protection to the infant for months, a higher level could have significant impact on infant morbidity and mortality.
Take, for example, the potentially dangerous Bordetella pertussis (whooping cough) bacteria, which has the potential to cause significant infant mortality. It has been shown that the placental blood does contain anti-pertussis antibodies 33,34. Although the authors point out that the levels are not necessarily always high enough to provide complete protection, it would seem to be beneficial nonetheless.
Placental blood has also been shown to contain antibodies to other dangerous and potentially deadly infectious agents such as Haemophilus influenzae type b (Hib), Streptococcus pneumoniae and Neisseria meningitidis, among others 34.
Could a widespread acceptance and practice of LC cause a reduction in these life-threatening diseases? If true, this could have an influence on infant vaccination policy by altering the risk/benefit analysis.
Breastfeeding Regarding possibly the strangest association, how is it possible for LC to improve breastfeeding rates? Well, no one is really sure, but a 1991 report did show a significantly higher breastfeeding rate with LC 35.
One theory is that the LC newborn has more strength (possibly due to greater blood volume and higher blood pressure). They may therefore be in a better position to successfully nurse, especially with first time mothers, where both mom and baby are attempting a new feat. Additionally, it has been reported that the increased early contact between mother and baby that often occurs with LC might improve breastfeeding rates 16,36.
Since breastfeeding has been shown to provide numerous and significant health benefits, this needs to be taken into consideration when discussing the issue of cord clamping.
Vitamins, Minerals, and Hormones It also stands to reason that along with the additional blood volume, the infant receives additional quantities of various nutrients such as vitamins and minerals, as well as hormones, which could provide many health benefits. For example, additional quantities of vitamin K might help prevent some cases of vitamin K deficiency bleeding in newborns, which often prove fatal. This might also reduce the need for neonatal vitamin K prophylaxis.
As another example, consider the trace mineral chromium. Additional quantities could improve insulin sensitivity, thereby improving blood glucose levels and reducing strain on the infant's pancreas by requiring a decreased level of insulin production. The fetal blood supply also contains many hormones, some produced by the placenta and others obtained from the maternal blood supply. The greater supply of hormones provided by LC could provide numerous health benefits. As an example, thyroid hormones are known to easily cross the placenta 37 and could exert positive influences on the infant's basal metabolism. Is it possible that LC could even help reduce the effects of hormonal deficiency disorders, such as Cretinism?
Additional Benefits The placental blood also supplies a great number of stem cells, which have the unique capability of dividing into specialized cells, replacing those that die or are lost. This additional supply could have a positive influence on the health of newborns 30.
In addition to the potential health benefits, LC may actually result in financial savings for the healthcare industry by reducing costs associated with the treatment of premature infants, such as reduced blood transfusions and other neonatal care procedures 21,30. Maybe health insurance companies should take a look into this issue, as it may be a unique opportunity to reduce costs, while improving health at the same time.
Possible Disadvantages and Risks Critics of LC cite several drawbacks, most commonly referring to the increased maternal bleeding which, as previously discussed, posses minimal risks to the mother, especially in a hospital setting. However, there are some situations where the risks of LC seem to be elevated. Some of these are listed in Figure 4.
An increased incidence of sepsis in infants occurs with LC when antimicrobial medications are given to the mother prior to birth. Because of this, it has been recommended that when the mother is given these drugs, as is often done following c-sections, the cord should be clamped prior to their administration in order to prevent neonatal exposure 49.
In addition, it has been shown that LC results in adverse effects on the infant when general anesthesia is used on mother, as often occurs with an emergency c-section 6. It has also been alleged by one study that no significant placental transfusion takes place with a c-section delivery, even after 3 minutes 8. However, other studies contradict this assertion 23,42. A possible cause of reduced transfusion in a c-section could be the lack or diminished strength of contractions, which seem to play an important role in the movement of blood from the placenta to the infant. It may be possible, therefore, to improve the rate of transfusion through the administration of oxytocin, thereby stimulating contractions 55.
Although no adverse effects of a moderate placental transfusion were found, one study warned of potential circulatory overload, hyperviscosity and polycythemia at term deliveries if "excessive" placental transfusion were allowed 17. This hypothesis, however, has yet to be adequately demonstrated, and therefore in my opinion can not be used as a basis for a medical intervention.
Additionally, a 1998 study expressed the opinion LC represents no risk to the newborn and that some problems which have occasionally been attributed to LC (e.g., polycythemia) may be the result of the routine vitamin K injections given to all newborns when combined with LC, rather than LC alone 53. If true, this could have a profound impact on the risk/benefit analysis for the standard procedure of administrating neonatal intramuscular vitamin K prophylaxis to all infants.
Lastly, LC may be medically contraindicated in the case of Rh sensitization, where an Rh-negative mother is giving birth to an Rh positive infant 2. Despite the occasional negative report, the WHO states that when LC is performed after the ceasing of pulsation (approx. 3-4 minutes), adverse effects have not been reported 2.
What is the optimal time? Even a very short delay in clamping can result in significant placental transfusion. After only 30 seconds, approximately 10-20ml/kg of placental blood transfer occurs in a vaginal birth 8. However, 30 seconds is certainly on the lower end of the spectrum, with most proponents recommending times ranging from 1 minute up to the cessation of cord pulsation, depending on conditions including gestational age, birth weight, type of delivery, and degree of risk for complications, including Respiratory Distress Syndrome (RDS).
For premature babies, it has been recommended that clamping be delayed for 1 to 1.5 minutes by one study 10, with another recommending 3 minutes 5. What to do?The question of what to do with the cord does not arise in the animal kingdom, since most herbivores tear it and carnivores chew it, which is of course followed by eagerly consuming the placenta, not letting any of the valuable nutrients go to waste 52.
Throughout a vast majority of their existence, humans have left the umbilical cord alone, at least until the placenta was delivered. This practice was replaced, in western society, during the seventeenth century with one of cutting it and tying it off, leaving a short stump 52.
According to the WHO 2: Late clamping (or not clamping at all) is the physiological way of treating the cord, and early clamping is an intervention that needs justification... in normal birth there should be a valid reason to interfere with the natural procedure.
It is important to realize that EC is a medical intervention and therefore needs to be medically justified. The fact that the practice of early cord clamping is a medical intervention, incompatible with natural physiological processes, is a concept that is often expressed in medical literature30,20,54 but seems to have a difficult time finding it's way into the delivery room.
Summary and Conclusion An editorial in the British Medical Journal had a startling and unfortunate observation that may apply not just to cord clamping, but to other common medical practices as well 16: Immediate cord clamping is currently routine practice, but its widespread acceptance was not preceded by studies evaluating the effects of depriving neonates of a significant volume of blood. Simply by providing a greater supply of oxygen, antibodies, vitamins, minerals, hormones, and other nutrients to the newborn, many potential benefits may be seen from LC. As stated by one researcher, by employing placental blood, rather than discarding it, many benefits could reaped 30. Therefore, unless medically contraindicated for a particular birth, there is much evidence that it makes sense for cord clamping to be delayed to allow for placental transfusion. This practice seems to be fairly low-risk, in most cases, and potentially quite beneficial. Has the time has finally come for this to become the standard medical practice rather than the exception? I would urge those in the clinical research setting to look at this issue closer, possibly addressing some of the potential impacts that have yet to be looked at (see Figure 5). Late cord clamping, although not technically part of "alternative medicine", is an excellent example of how a simple, low-cost, non-pharmacological, non-surgical, and non-technology based intervention may result in long term and far reaching health benefits.
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