Trust umbilical cords?

Natural childbirth and homebirth advocates get very excited about umbilical cords, specifically nuchal (neck) cords, the medical term for an umbilical cord that gets wrapped around the baby’s neck. They get excited because they believe that obstetricians dramatize the risk of nuchal cords (“the baby could die”) when they aren’t dangerous at all. As usual, natural childbirth and homebirth advocates are wrong on this point and the reason is that they fundamentally misunderstand when and why a nuchal cord dangerous.

How does an umbilical cord get wrapped around the baby’s neck in the first place. The reason is that for most of pregnancy, the baby has a lot of room to move and the cord is relatively long. Moving around, up and down, and somersaulting, the baby can easily get the cord wrapped around itself. Most of these loops will slip off at some point, generally without causing a problem. There is the possibility, however, that even if the loops eventually slip off the baby, a true knot will have been formed but many true knots never cause a problem.

Even more likely, a loop may get stuck around the neck because it is more slender than the shoulders below it and the head above it. Contrary to popular belief, the danger of a nuchal cord has nothing to do with the fact that it is wrapped around the baby’s neck. Since the fetus does not breathe, compressing its neck has no impact on whether there is adequate oxygen in the blood. In other words, the effect of neck compression is fundamentally different than if the neck of a child or adult is compressed.

In order to understand the danger of a true knot in the cord or a nuchal cord it helps to think of the cord as similar to the air line of a deep sea diver. It’s easy to understand that if a diver moved around such that he created a true knot in an air line, it could pose a serious problem. If the knot isn’t pulled tight, there is no problem. The oxygen can pass easily through the loop. However if the knot gets pulled tight because the diver pulls on the air line by diving down deep or it gets pulled tight by being snagged on something else, the supply of oxygen can get cut off and the diver could die.

Similarly, a loose true knot in the umbilical cord is not a problem for the fetus because the oxygen continues flowing through the loop. However, if the knot gets pulled tight, either by the cord being pulled as the baby descends into the pelvis or the cord getting pulled by being snagged on an arm or leg, the baby will be deprived of oxygen and die

This picture of a true knot (a close up of the picture at the top) was sent to me by a reader. It was noted at her 3rd C-section. It is easy to understand that had the knot been pulled tighter, the baby might have died..

If an air line got wrapped loosely around a diver’s neck, the oxygen would keep flowing through it. However if the loop or loops were so tight as to cut off flow within the line, the diver will die. Of course a diver could actually be strangled by a loop or loops of cord, but a baby cannot. Therefore, the issue with a nuchal cord is NOT the fact that it is wrapped around the neck. The issue is whether the loop is pulled tight enough to cut off the flow of blood and therefore of oxygen.

The bottom line is that true knots of cord are not necessarily dangerous, but there is no way to no beforehand whether the knot will tighten during the course of labor and cut off oxygen to the bay. Similarly, a nuchal cord is not necessarily dangerous; in fact most nuchal cords are loose and therefore do not threaten the baby. Once again, though, there is no way to know beforehand how the loop or loops around the neck will be affected during labor. The higher the number of loops, the shorter the remaining cord, and the more likely that the cord will be fatally compressed during labor. However, even a single loop can be pulled tight during the descent of the baby and the baby will die for lack of oxygen.

Ultimately, when NCB and homebirth advocates “trust birth,” they are trusting that there are either no knots or loops in the cord, or that if they exist, they will not be pulled tight. But that makes no more sense than a deep sea diver trusting that he can assume that there are no knots in his air line and not worry if the air line gets wrapped around his neck. Obviously, in the case of the air line, trust has nothing to do with it, and, in direct contrast to what NCB and homebirth advocates proclaim, in the case of the umbilical cord, trust has nothing to do with the presence or absence of knots and loops.

The only way to know if a knot or nuchal cord is hindering the flow of the blood to the baby is to monitor the baby’s heart rate. Without monitoring, the supply of oxygen to the baby could completely stop during labor and no one would know until the baby was born dead.

  • catalina

    I just watched your video “The Truth About Homebirth Midwives” and found it to be extremely factually inaccurate, at least from my own experience. Perhaps your information is just outdated? I am currently in college fulfilling all of the pre-requisite classes I need in order to apply to a direct entry midwifery program at SUNY Downstate. Among the pre-requisites are a statistics course, basic biology, human nutrition, anatomy and physiology with labs, chemistry, and several psychology classes. I am not eligible to even apply for the program without my bachelor’s degree and all of the classes I listed and more. The course of study is at a master’s level. Both the nurses in the program and those, like me, who are not nurses, will be taking classes together and taking the same qualifying exam for the initials after our names. They will be CNM’s and I will be a CPM. We will both be able to practice in hospitals. We will both be able to do home births. I hope to gain experience in both. You seriously need to take down that video unless your purpose is to knowingly deceive others. I happened upon your blog and am very interested to hear an opposing viewpoint to my own. I am hoping to learn something here – but seeing how inaccurate your video is makes me question everything else I might read here.

    • Amy Tuteur, MD

      The SUNY Downstate is not a CPM program, it is a CM program, totally different. A CM is a credential awarded by the American College of Nurse Midwives. A CPM is a mail order credential, only recently “strengthened” to require a high school diploma.

      • Squillo

        Correction: the CM and CNM credentials are awarded by the American Midwifery Certification Board, not the ACNM.

      • catalina

        OK, my mistake. I know lots of CM also get the CPM from NARM. Your point that there is the potential for a CPM to be undereducated in comparison to a CNM is strong. I can see why people would be leery of someone who is ignorant of possible complications in birth, someone who doesn’t know how to recognize when the risks of natural birth are outweighing the risks of interventions would be a dangerous practitioner. You really have to assess CPM’s (and really, any healthcare practitioner when it comes down to it) on a case by case basis. Ina May Gaskin, a renowned figure in midwifery circles, is a self taught lay midwife with a CPM. She has delivered hundreds upon hundreds of babies safely, at home, over a period of decades. I would trust her knowledge of normal uncomplicated delivery and when to recognize what is not normal over any OB just walking out of a medical school where they never once attended even one natural, unmedicated, no intervention birth. She has strong, proven, undeniable track record I would not underestimate the power of experiential learning. Midwives who get the CPM alone are required to apprentice under an experienced, licensed midwife and they do need to pass NARM’s test at the end. It is a non-traditional route to learning for sure, but I would not dismiss all CPM’s as ignorant on that basis. Anymore than I would judge every OB as competent simply based on their degree.

        • Karen in SC

          I don’t know what you mean by “just walking out of medical school.” By the time OBs are in practice, they have completed a years long residency and delivered thousands of babies. INCLUDING natural, unmedicated, no intervention births. I had two of those myself, and know of dozens of other women who did the same.

        • PrimaryCareDoc

          I really wish NCB advocates would stop repeating this trope that OBs never see natural unmedicated births. When I was a med student, I saw at least 5. And I only did 3 weeks of OB!

          So please, get a new talking point!

        • DaisyGrrl

          I’d take a newly minted OB over Ina May Gaskin any day. I’d rather have an unaccompanied birth than trust myself to that loon.

          As someone who appears to be committed to getting a proper education in midwifery, please think long and hard about the philosophical underpinnings of the Ina May brand of midwifery. It is not evidence based and is not friendly to women or babies. I encourage you to look around this website and read the linked studies.

          CPMs are by definition ignorant. For the most part, they have not obtained specialized post-secondary education and do not know what they are doing. I applaud you for getting a proper education and wish you the best of luck in your studies. But please understand that you are not doing yourself any favors by denigrating medical professionals with extensive postgraduate educations in favor of people who can’t be bothered to go to school but want the same recognition as those who do.

        • Trixie

          That’s because Ina May Gaskin MADE UP the CPM and then awarded it to herself so she would sound more qualified to do something she has no training in. That’s like me sitting here in my living room and declaring that I’m a Certified Professional Skydiving Instructor because I’ve flown on commercial airlines before.

        • The Bofa on the Sofa

          This is just the long way of saying that not all CPMs are quacks.

          Which is a pretty bad indictment of the profession.

  • EE

    “Contrary to popular belief, the danger of a nuchal cord has nothing to do with the fact that it is wrapped around the baby’s neck. Since the fetus does not breathe, compressing its neck has no impact on whether there is adequate oxygen in the blood”

    That’s all well and good, but do you care to explain why cutting off the oxygenated blood to the developing brain is in no way endangering the fetus, Dr. Tuteur?