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Some comments about "Anatomy of A Fetus: Circulation and Breathing"

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These are easy to read and understand and are beautifully presented.

In response to Anatomy of A Fetus: Circulation and Breathing

This is a beautifully clear and interesting introduction to the complexities of the changes that occur in the circulatory system as a fetus becomes a newborn.

There are so many things about pregnancy and birth that are miracles, and the conversion from fetal circulation to newborn circulation is one of the most wonderful.

However, I did want to make a few comments about this article:

About three-quarters of the way down the page, we read:

"With delivery, the life line of the umbilical cord is severed.  Air hunger develops, and a reflex causes the newborn child to gasp for air."

It is not air hunger that causes the newborn to take a first breath, and it is certainly not necessary for the cord to be cut in order for the baby to start breathing.

The doctor talks much about the natural wonders of embryonic development and the amazing processes that happen naturally and spontaneously, but then betrays his reality of overly interventive birth in assuming that the umbilical cord is severed immediately at birth.  I am quite certain that nature didn't assume that a birth attendant would be standing nearby, scissors in hand.

In reality, babies start to breathe right away even if the cord is left untouched.  It is not air hunger that stimulates a baby to take its first breath.  It is likely the stimulation that comes from the shock of cold air and the sudden exposure to light and noise.  Even dim lights and low noises seem very startling to a baby who's only used to life in the womb.

Both Williams _Obstetrics_ and Varney's _Nurse-Midwifery_ concur: "The phenomenon that occurs to stimulate the neonate to take the first breath is still unknown.  It is believed to be a combination of biochemical changes and a number of physical stimuli to which the neonate is subjected, such as cold, gravity, pain, light and noise, which cause excitation of the respiratory center."

I personally have noticed that a baby's "startle/Moro reflex" is the perfect motion for expanding the lungs . . . the arms flung wide and then retracted.

Beyond the question of what stimulates the baby to take a first breath, we can look further at the triggers for the changes in the foramen ovale and ductus arteriosus. The delicate process of rerouting the circulatory system depends on the intricate interplay of blood gas levels that occurs naturally as there is a gradual shift from reliance on umbilical cord oxygen to reliance on air breathed into the lungs.  Sudden severing of the umbilical cord is an unnecessary and dangerous meddling with this process. Some people refer to this as premature amputation of the placenta because the baby is still using oxygen carried through the cord from the placenta.

Many people have come to understand the importance of leaving the umbilical cord intact as long as the baby is still using it. Most people assume that once the pulsing in the cord stops, the baby is no longer using it.  This comes from a bit of a misconception that the pulsing is caused by the placenta and that the pulse is blood flowing from the placenta to the baby.  In actuality, the pulse is caused by the baby's heart and represents the pulsing flow of blood away from the baby, in order to be oxygenated through the placenta.

Babies are incredibly smart little critters, and they know the value of that precious life's blood.  They stop sending blood away from their body relatively early after birth, but they continue to receive oxygenated blood flowing from the placenta for some time after the birth, even after the placenta has separated, detached and been delivered.  There is no scientific research regarding how or when this flow stops - the erroneous assumption has been that the baby doesn't need to continue receiving blood from the placenta after birth.

Again, there is no evidence to support the belief that it is safe to sever the umbilical cord within seconds or even minutes after birth.  It would be nice if medical science could explore this key question, but until research provides answers, we need to err on the side of caution.

Some things that research can tell us about premature cord cutting - it deprives the baby of valuable blood volume, and it deprives the baby of long-term iron stores.  Here are some references:

Cord Closure: Can Hasty Clamping Injure the Newborn? George M. Morley, MB., CH. B, C July 1998 OBG Management. Excerpts at: http:

The above article discusses the great importance of the baby's continuing to receive blood from the cord and placenta after birth in order to supply the blood volume for pulmonary perfusion. As the author so clearly points out, the lungs are poorly perfused prior to birth, meaning that there isn't much blood flowing through the blood vessels to the lungs.  Rather quickly after birth, the baby's system needs to increase the blood volume in the lungs so that oxygen can be transported from the lungs to the rest of the body in the blood.  Nature assumes that blood from the placenta and cord will be available to supply this vital blood volume, which is only the case if the umbilical cord is left intact.

Neonatal prevention of iron deficiency: Placental transfusion is a cheap and physiological solution. Pisacane A BMJ 1996 Jan 20;312(7024):136-7 Full-text article available at: http:

The above article discusses the clever system whereby the baby breaks down the blood to prevent dehydration in the early days and to store up iron for the first six months of growth.

Summarizing current research on the timing of cutting the cord, Enkin et al. in _A Guide to Effective Care in Pregnancy & Childbirth, (2nd ed)_ write on p. 239:

"Active management of the third stage of labour usually entails clamping and dividing the umbilical cord relatively early, before beginning controlled cord traction.  Pre-emptying physiological equilibration of the blood volume within the fetoplacental unit in this way may predispose to retained placenta, postpartum haemorrhage, fetomaternal transfusion, and a variety of unwanted effects in the neonate, respiratory distress in particular.  Delayed cord clamping results in a placental transfusion to the baby varying between 20 and 50 per cent of neonatal blood volume, depending on when the cord is clamped, at what level the baby is held before clamping, and whether oxytocics have been administered."

Research tells us that immediate clamping of the umbilical cord is actively harmful to the baby, and responsible practitioners everywhere must work to change their own practices and educate their peers.

I think the following statement can stand on its own merit, without benefit of research:  "Newborns in respiratory distress are most in need of continuing oxygen supply from the umbilical cord."  Yet these are the newborns whose cords are likely to be cut most quickly.  Why is this so?  It is simply because the newborn resuscitation equipment is across the room rather than immediately accessible at the bedside.

We have technology that allows us to perform surgery on a baby _in utero_, but we can't figure out how to move the resuscitation table to the newborn in respiratory distress rather than the other way around.

I have heard rumors that cutting the cord represents a legal cutting of the obstetrician's responsibility for the newborn's treatment.  This is the best explanation for why distressed newborns have the umbilical cord cut most quickly, but I truly do not want to believe that an entire medical system is built on the premise that limiting legal liability is more important than providing the best possible care to newborns.

Does anyone disagree that it would be beneficial for a newborn to be continuing to receive oxygen through the umbilical cord while resuscitative measures are being taken?  Why, then, is this situation not changed?

In addition to the physical ramifications of immediate severing of the umbilical cord, there are psychological factors which are finally being explored by the Association for Pre- and Perinatal Psychology and Health.  Although it is hard to measure emotional or psychological stresses at birth, it is generally accepted that a newborn will have a negative reaction to the sudden loss of oxygen from the umbilical cord.  This "air hunger" isn't necessary in order for the baby to start breathing, but if it causes the baby to start gasping for air, we can assume that the baby is feeling some panic or anxiety about this.

There's much, much more information about fetal circulation and cord cutting at http:

I understand that the doctor is an obstetrician and specializes in the mother's side of birth, so I wanted to add a few comments from the folks who specialize in the baby's side of birth. Here are some excerpts from the Neonatal Resuscitation Manual, produced by the American Academy of Pediatrics and the American Heart Association.

In particular, I'd like to provide some key information regarding the way labor and birth choices affect the newborn's adaptation to breathing.

Nature assumes that babies are born vaginally, which involves a rather tight squeeze on the baby's chest.  This helps to remove fluid from the lungs so they can expand more easily at birth.

However, the role of the vaginal birth itself is minor compared to the role that labor plays.  Even women planning a surgical birth should be informed that their baby will breathe more easily if some labor is experienced.

It is also important to provide accurate information about the effect that drugs have on the baby's respiration.  "Shallow, ineffective respirations may occur in infants who are depressed as a result of maternal drugs or anesthesia.  These gasping, irregular respirations may be insufficient to properly expand the lungs."  This is such a serious problem that Narcan (stands for Narcotic Antagonist) is routinely used at births where mothers have received narcotics during labor.

There is not much research about the effects of epidurals on newborn breathing, but we do have numerous studies showing that epidurals interfere with the hormonal parade of normal labor and birth.  In particular, we know that epidural anesthesia blocks the production of endorphins and adrenaline in the mother's system, which also prevents them from being passed through to the baby.  This hormone deficit may explain the latching and nursing problems that nurses and lactation consultants are reporting in babies born to mothers with epidurals.  It seems logical to assume that babies who are having trouble nursing probably had trouble with the once-in-a-lifetime challenge of jumpstarting respiration.

My comments have turned out to be much longer than I intended. This is a reflection of the gravity of a situation where birth attendants are blithely cutting the cord immediately after birth without understanding the serious detriment to the newborn.

This Web page is referenced from another page containing related information about Umbilical Cord Issues


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