Monday, September 20, 2010

The Umbilical Cord

By Kathy Petersen
posted with author's permission
read more from Petersen at: Woman to Woman Childbirth Education and here on Facebook


The umbilical cord is what connects the baby to the mother. Soon after conception, the baby (embryo may be the “correct” term for this stage of development) burrows into the lush uterine lining, and part of the embryo becomes the placenta while the rest of it becomes the baby, inside the amniotic sac. The placenta grows along with the baby, and although the mother’s and baby’s blood never mix, the placenta is where the oxygen and waste exchange happens–the mother’s circulatory system gives the baby oxygen and nutrients while taking away the baby’s carbon dioxide and waste.

Generally, there are no problems with this wonderful system; but occasionally, the placenta does not grow very big, or the umbilical cord can develop a knot, or wrap around the baby. Many home-birthing midwives will testify that maternal nutrition plays a vital role in a well-developed placenta, which only makes sense - "you are what you eat." Check out The Brewer Diet for more information on a healthful diet.

The umbilical cord can develop a knot if the baby moves through a loop in the umbilical cord. This happens very early in pregnancy, when the baby has ample room in the womb for these free movements; later, the baby is much more squished in the confines of the uterus. Most of the time, a knot is not a problem, but a “true knot” can potentially be so tight that it compromises blood flow through the umbilical cord to the baby. This later danger is very rare, and usually cannot be known before birth.

a "true knot"

Probably what most people worry about when it comes to umbilical cords is that they will be wrapped around the baby’s neck. This is called a “nuchal” cord (from the Latin word for “neck”). This is much more common, occurring in up to 25% of all births, but only rarely causes problems. My first son, for example, had the cord wrapped around his neck once, and the midwife couldn’t get it off before his body was fully born, but the cord was kept intact and my baby had no problems whatsoever. In fact, I did not even know it had happened until a few years later when I was looking through my copy of the birth records. What might cause problems is if the cord is wrapped around the baby’s neck and cuts off or diminishes circulation to the baby’s brain either in utero or as the baby is being born. But again, this is rare.

The typical response to a nuchal cord is to unloop it from the baby’s neck after the head is born and prior to full birth if at all possible; and if it’s too tight, to cut the cord and unwind it. (The cord will be clamped in two places, and the cut will be made between, to minimize blood loss to the baby, and mess on the floor from the placenta side of the cord.) Some birth attendants will instead “somersault” the baby out of the birth canal, keeping the baby’s head close to the mother’s body. This allows the baby to be born while still keeping the cord intact (occasionally, a nuchal cord might prevent the baby from coming out because it makes the cord too short). With the baby fully out, the cord can then be unwound from the baby’s neck or body, thus allowing the full amount of oxygen that sustained the baby inside to keep coming to the baby on the outside, while he makes his transition to breathing.

It may be possible to identify a nuchal cord with ultrasound, but there are some considerations you should have.

First, most nuchal cords do not cause problems. There are fetal tests that can be done if a nuchal cord is suspected or known that can reassure you as to fetal well-being (including you doing “kick-counts” at home to make sure your baby is moving adequately).

Second, ultrasound is not 100% reliable, and you have to judge the benefits vs. risks of this or any other procedure.

And finally, is a story one of my friends shared with me (she is a doula at a birth center, as well as childbirth educator). A couple discovered via ultrasound that their baby had a nuchal cord (after the woman was at term, but prior to onset of labor). The woman was terrified of the baby strangling herself, so she decided to have a C-section right then. The birth center offered to keep her overnight and continue to monitor the baby, and let her see that the baby was just fine, but she was too scared to accept. Within a couple of hours, she had had the C-section, and the doctor said there was no nuchal cord.

Babies move in utero; they twist and turn. It is easily understandable that the baby could wrap herself up in the cord, and then unwrap herself just as easily.



Related Information:

Nuchal Cord Midwifery Files

Umbilical Cord Around Baby's Neck: Dangerous or Not?

Neonatal Resuscitation: Life that Failed

Gloria Lemay: Cord Around the Neck

Unwrapping a Nuchal Cord [video]

Lotus Birth

In this video on pregnancy myths, OB/GYN Hakakha reminds parents (in the 7th section of this video) that the umbilical cord is often around a baby's neck while inutero and at birth and it is very rarely a cause for concern.





10 comments:

  1. My daughter had a nuchal cord that could not be adjusted before full delivery. I had a water birth, and she somersaulted in the water as she came out, with no help from my midwife. Pretty amazing.

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  2. I read that having a nuchal cord should be regarded as a good thing as it ensure that you don't end up with a cord prolapse...

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  3. I think mamas need to remember that cord compression can occur ANYwhere and in ANY position. It's not the "neck" part that makes it dangerous, it's the compression part.

    The number one way to prevent compression is to have a drug-free, peaceful birth. When you introduce induction, especially with drugs such as Pitocin, you increase the strength of the contractions and remove the natural ebb and flow of them, creating an atmosphere for compression, whether that happens when the cord is around the neck, above the head, around the shoulder, body, legs, etc.

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  4. It is hard to read this post when you have experienced one of those "very rare" times when your baby dies as a result of a compressed cord (during a very peaceful birth, btw). It isn't so much that I disagree with what you are saying-- statistically it is true-- but it is how hard it is to be one of those statistics. And then to try to birth again, peacefully, and trust it would work out (it did...three more times). But still.

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  5. In my literature review on nuchal cords I found that the factors associated with a nuchal cord are: a long cord; a male baby; an active baby; labour. The last one 'labour' is because during labour the baby rotates through the pelvis, often wrapping the cord as they go. This is why there are less nuchal cords found at elective c-sections than at vaginal births.
    Also cutting the cord is extremely dangerous and has resulted in successful legal action in cases of shoulder dystocia after cutting a nuchal cord.

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  6. first, i love your blog. i appreciate that someone is finally willing to discuss these issues. i have had 3 children. two are still living. both of my living children were breastfed (the 2 yo is still nursing, in fact), co-slept (again, one still does), were worn in a sling, are intact, and are unvaccinated.

    i have to agree with anonymous though. in general, i don't disagree that it is not common for a nuchal cord or cord compression to be an issue. but it isn't all that rare either.

    i realize that you don't want to scare expecting mothers, but it bothers me to have a medical professional downplay the reality of the situation. my first son died, from what we believe to be a cord accident, at 41 weeks gestation. the truth is we will never know.

    yes, kick counts can help, but they aren't a cure-all. my son's heart rate was 142 within 12 hours of his death, but he wasn't moving--he wasn't a terribly active baby at any point.

    the truth is that there are nearly 30,000 still births in this country every year. about half are late term. about the same number have no known cause. was it a cord accident? most will never know. torsion, where the cord is physically twisted, is considered a cause of death in horses. but in humans it is considered an artifact of death.

    and my 2 yo's delivery was very nearly a c-section because she had her cord around her next twice and once around her wrist. my water broke, but she would not come down to apply any pressure on my cervix. so i didn't dilate. and when it came to pushing, i worked for 2.5 hours. i could feel her come down and then she would pop out again and again. she was finally born vaginally.

    i don't mean to freak anyone out, but "very rare" is not a phrase that should be use in this situation. it very often works out just fine, but it hurts like hell to be 1 in 115. so i can't just sit back and let it go.

    i tell women, absolutely do kick counts, but if you ever feel that anything isn't right. run! do not walk. run to your care professional. and do not take "no" or "it's nothing" or, in this case, "it's very rare" for an answer. sometimes a healthy amount of fear serves a purpose.

    to anonymous, blessings to you. my son would be 7 years old.

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  7. My baby had a double nuchal cord, around her neck and her torso. She failed "kick-count" tests in the few days before her birth. When I went into labor, her heart rate dropped dramatically during contractions.

    What saved her life was 1) I didn't have my water broken, thereby allowing her cord not to be further compressed, 2) I had a very fast labor, and 3) the fact that she had one of the longest cords the nurses had ever seen. As it was, when my baby's head came out, the doctor had no choice but to cut the cord. The baby was gray and floppy and not breathing, with a one-minute Apgar of 4.

    However, thanks to the team of NICU nurses that were in the room, who knew that my baby was in distress and were ready for her, my baby had a five-minute Apgar of 9. She is a healthy and intelligent 3 year old today.

    Nuchal cords aren't usually a problem, but sometimes they are. I think the point about a natural, unmedicated birth is a good one, because interventions of any kind can put further strain on a baby already strained by a nuchal cord.

    You can read more about my baby's birth here: http://notfinishedyet.wordpress.com/2008/08/24/the-miracle-of-birth/

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  8. my 1st , 2nd and 3rd all had the cord round their necks 1st and 2nd the mw cut the cord before i birthed the body 3rd the mw just looped it over her head before i birthed her body

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  9. I'm sorry for those who have lost children to cord compression. It really is terrible, and when it's your child, it doesn't seem "rare." But the fact is, 1/115, if that is the most current statistic, is still rare. And saying that a cord around the neck is terrifying leads to more aggressive intervention - especially when it is RAREly needed. My son had the cord around his neck 2 times and a very long cord. My daughter had it around her neck once. This baby - who knows. The thing is, as much as we hate to say it about babies and all the wonderful and happy that goes with them - sometimes things go wrong that no one can prevent. I've lost two children to miscarriage, but I can't go around telling everyone who says "congratulations" on a pregnancy, "Well, you never know..."

    What I was going to comment on before reading the others, though, was the part of the post about ultrasound possibly not being the best way to determine nuchal cord. One of my closest friends from college had multiple ultrasounds during her pregnancy, especially the second half, because she was told that the baby's intestines were outside his body. Over and over again, this same doctor kept saying that he needed to be born by c-section because of this horrible complication. So she had the section... his intestines were fine, his abdomen was completely closed... it was his umbilical cord this ass had seen all along. His response? "Oops. Oh well."

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  10. Babies are designed and supported by our bodies to withstand hypoxia at birth - it is one of the many reasons why maternal hormones are so important.
    A baby with a tight nuchal cord or other reasons for cord compressions are commonly born hypoxic - which is why they need their cord intact MORE THAN EVER!
    Without adequate perfusion of placental blood (the baby's blood!)neonatal respiration is placed at an unacceptably high risk. Just administering oxygen to does provide adequate blood volume for all the organs and can lead to organ damage (brain damage).
    Even if resuscutation is successful the low red blood cell count remains an issue, with infant anaemia linked to irreversible brain damage - most often diagnosed as developmental delay.

    The baby can be white, compromised, low score Apgar at 1 min, but that is what the rapid pulsation of the cord is designed to do. Revive and reoxygenate the baby at birth.

    All nuchal cords should be left alone as much as possible, with support of somersault technique if need be, to protect the momentum of labour and chance of successful birth/ placental transfusion. Cutting the cord should be last ditch effort, followed by whole blood transfusion to protect from the extreme blood loss experienced by baby.

    See my son's story here: http://giftedbirthsupport.com/2011/06/01/birth-story-nuchal-cord/

    Kate

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