Nuchal Cord Research

When a fetus has the umbilical cord wrapped around his or her neck, it is called a “nuchal cord” — from the Latin word for “neck”. The cord can also be wrapped around another body part, such as the hand, foot, trunk, or perhaps even all of these. A nuchal cord is usually not a problem, being present in perhaps a quarter or even one third of all births; but sometimes it can cause a problem.

In combination with a short cord, it can prevent the baby from being born — for example, if the placenta is at the top of the uterus, and the cord loops around the baby’s body and then wraps his or her neck so that there is no extra length of the cord, the baby may literally be trapped in the uterus. It’s not common for this to happen — most babies even with nuchal cords wrapped two or even three times, or with body entanglements, can still be born vaginally, because the length of the cord allows it; but sometimes they just can’t (perhaps the baby is entangled in the cord too close to the placenta, or the cord loops over his body from shoulder to groin and back again). We’re all glad of intervention being available in these cases. [I even read of one woman who normally chose unassisted birth having a strong feeling that she ought to have a C-section with her current pregnancy, and when the baby was born by C-section, the cord was so super-short that they had to cut the cord to get the baby completely out of her uterus — obviously, this sort of problem is also super-rare! I also read of a woman who discovered that the umbilical cord was between her baby’s head and cervix, so in the weeks leading up to birth, she talked to the baby and asked him or her to hold onto the umbilical cord and keep it out of the way so it wouldn’t cause problems (such as umbilical cord prolapse); when the baby was born, s/he was holding the cord, just like the mama had asked. Coincidence? You decide.]

Here is an article for your files — an editoral from an ultrasound journal in 1999 which discusses research into nuchal cords. Whether you agree with everything that is in there or not, the bibliography is valuable for naming other studies that have been done, which is why I’m keeping it, in addition to the interesting discussion. [Sometimes links to Wiley InterScience don’t work right, so you can find this article by looking in Ultrasound Obstet Gynecol 1999, volume 14, issue 1.] And this article differentiated between tight and loose nuchal cords, finding that tight nuchal cords were associated with adverse outcomes at a much higher incidence than either loose nuchal cords or no nuchal cord.

Of course, not all articles noted significant differences with nuchal cords versus no nuchal cords (not sure if they distinguished between tight and loose, but that seems like a no-brainer to me to do that), so the jury is still out as to whether nuchal cords and entanglements cause statistically significant problems for babies; but it is also understood that nuchal cords can cause problems with certain babies. After all, if one baby out of a million dies before or after birth because of a nuchal cord, but the rest of the up to 37% of babies with nuchal cords are just fine, then it’s not statistically significant. But it is very significant to the parents of that baby who died.

Another confounding factor is the type of nuchal cord. It can be “sliding” (Type A) or “locked” (Type B); other sources distinguish them as “wrapped” (Type A) and “hitched (Type A). Type B is assoicated with a higher rate of complications with the baby, because it can tighten around the baby as the baby moves (I’m picturing a necktie or a noose, but may be a little off on that), but even this does not automatically require a woman to have a C-section (but if it is known beforehand, it would seem prudent to me to be more vigilant during labor, as well as in the weeks leading up to it).

Nuchal cords that are identified prenatally can resolve spontaneously, so if you have an ultrasound and a nuchal cord is noted, you shouldn’t panic. Here is an abstract for a case study published in 2003. In short, the woman had a breech baby (at 34 weeks) that she wanted to try to have turned externally, so she wouldn’t have to have a C-section. When an ultrasound was done (at 36 weeks), it was noted that the baby had a double nuchal cord, so an ECV wasn’t done. Two weeks later, an ultrasound showed that the nuchal cord was gone, so she was given an ECV and went on to have an uncomplicated vaginal birth. [This could also be a reason to decline a scheduled C-section due to breech, because babies can be turned, or can turn spontaneously, in just a few minutes, thus avoiding a C-section entirely… assuming you can’t have a vaginal breech birth for whatever reason.]

So, to sum up:

  • many babies have nuchal cords, and it is usually no problem (my firstborn had a loose nuchal cord, and it was no big deal)
  • nuchal cords can resolve spontaneously
  • occasionally nuchal cords and cord entanglements can cause a problem, either with compromising the flow of blood between placenta and baby, or by strangling the baby (yeah, I know, the baby doesn’t breathe through the throat, but blood still needs to get to the brain through the neck — think Vulcan death grip or whatever — lack of oxygen to the brain can be either due to not enough oxygen in the blood [either due to breathing in the born, or placenta in the unborn], or to not enough blood to the brain [due to something wrapping too tightly around the neck, constricting the carotid arteries, whether in the born or the unborn]), and this can take place prior to labor or during labor, so women need to be aware of fetal movements, and particularly do fetal kick counts
  • nuchal cords seem to be associated with more fetal distress or abnormal fetal heartrate patterns during labor and also cerebral palsy, although not all studies reached that conclusion (possibly due to failure to distinguish between tight and loose nuchal cords)
  • nuchal cords may also play a role in some babies having difficulties during labor and birth, including failure to descend, if the baby is wrapped up in the cord enough (not typical, but possible, and it does happen)
  • the cord can wrap around the neck in two ways, with one being worse than the other and associated with more rates of complications including perinatal death
  • also regular ultrasound may not reliably discover nuchal cords, but color Doppler imaging has a high reliability
  • induction of labor is an independent risk factor for nuchal cord

Finally, fetal compromise can happen due to a number of reasons and nuchal cord is just one of them, so it is wise for all pregnant women to be aware of fetal movement and to get checked out should they note a significant decrease in movement. It could save your baby’s life.

10 Responses

  1. Very interesting. Often when a nuchal cord will not reduce and the babies head is out, the HCP will clamp and cut the cord. This often results in a compromised infant. I also worry if they clamp and cut, what if we have a shoulder dystocia? Ykies!!!

    • Yes, I’ve heard that c/c a tight cord is typical, and I understand the logic — and it may even be necessary sometimes. But I’ve also heard an alternative which allows the cord to be kept intact, and that is basically to “somersault” the baby out, which allows the head and nuchal cord to be kept as close to the perineum as possible so that it doesn’t tighten any more. This way, if the baby needs a bit of help starting breathing, s/he’s still got the cord delivering oxygen from the placenta.

  2. It is interesting how sometimes it can cause problems and sometimes not.

    My first emergency cesarean – due to distress, most likely due to cord being tight around neck 2 times.

    2nd baby, I told him, have short cord, don’t get tangled. He did have a short cord. They had to cut his cord in order for him to reach my stomach after he was born.

    3rd baby I let go of that fear and didn’t really think about cords at all. Bryson was born with the cord loosely around his neck 3 times with no issues at all.

    So I try to tell moms, nuchal chords in and of themselves are nothing to worry about. If there is a problem, it will be picked up with intermittent monitoring.

  3. My first baby was induced and didn’t have a heartbeat and was not breathing as she was delivered due to a tight nuchal cord (only wrapped once). They did a shoulder dystocia maneuver, cut the cord, then revived her. In her case there would have been no time for emergency c-section. She ended up being fine, but truly almost wasn’t, it was real dicey for quite a while. It was a real miracle.

    I don’t understand if you are saying that induction can be related to the tight nuchal cord when you say “induction of labor is an independent risk factor for nuchal cord”. Also, whether you are saying that cutting the cord is bad in the case of a baby without a heartbeat.

    My second baby had shoulder dystocia (induced at one week overdue). I was talked into a C-Section on the third. My OB (who wasn’t at the birth – it was a different doctor at the hospital) said I have my choice to do VBAC or C-Section for my next. I’m trying to educate myself.

    Thank you in advance.

    Cathy

    • Cathy, I’ve looked to see if there is more research on this, and haven’t found any other studies that discuss inductions and nuchal cords. My take on the study I linked to, based on the conclusion the researchers reached, is that somehow being induced increases the odds that the baby will have a nuchal cord. It may be possible that for some reason, babies with a nuchal cord already tend to be induced at a higher rate; or perhaps babies that are not induced tend to unloop themselves from the cord during labor or birth. Maybe further research will give greater understanding in how these two seemingly unrelated things correlate. But as it stands now, it appears that induction increases the risk that the baby will have a nuchal cord. Of course, most nuchal cords will not cause the problem your baby suffered — most will be loose, and won’t knot around the neck. My opinion is that it’s better for the baby to stay attached to the umbilical cord until the cord closes, which is typically at least several minutes after birth. If you read the comments following this post, you’ll see that not everybody agrees with that. At the least, though, I think there needs to be good reason shown that *not* clamping the cord causes problems. Many times, even when the mom requests that the cord be kept intact, the cord will be cut, so that the baby can be taken to the oxygen table, and/or for further measures to help him breathe. This is likely what happened in your baby’s case. It makes sense to me that if the baby is not breathing, then the baby should be kept attached to the placenta, with any additional paraphernalia that is needed being brought to the baby, instead of the baby being taken elsewhere. But this would be extremely rare to see in hospitals — most of the time, they just kick into resuscitation mode, and follow their normal procedures, which includes cutting the cord, and taking the baby to the table where the oxygen is. Kathy WomanToWomanCBE.wordpress.com katsyfga.wordpress.com

  4. Cathy,

    I’ve looked to see if there is more research on this, and haven’t found any other studies that discuss inductions and nuchal cords. My take on the study I linked to, based on the conclusion the researchers reached, is that somehow being induced increases the odds that the baby will have a nuchal cord. It may be possible that for some reason, babies with a nuchal cord already tend to be induced at a higher rate; or perhaps babies that are not induced tend to unloop themselves from the cord during labor or birth. Maybe further research will give greater understanding in how these two seemingly unrelated things correlate. But as it stands now, it appears that induction increases the risk that the baby will have a nuchal cord. Of course, most nuchal cords will not cause the problem your baby suffered — most will be loose, and won’t knot around the neck.

    My opinion is that it’s better for the baby to stay attached to the umbilical cord until the cord closes, which is typically at least several minutes after birth. If you read the comments following this post, you’ll see that not everybody agrees with that. At the least, though, I think there needs to be good reason shown that *not* clamping the cord causes problems. Many times, even when the mom requests that the cord be kept intact, the cord will be cut, so that the baby can be taken to the oxygen table, and/or for further measures to help him breathe. This is likely what happened in your baby’s case. It makes sense to me that if the baby is not breathing, then the baby should be kept attached to the placenta, with any additional paraphernalia that is needed being brought to the baby, instead of the baby being taken elsewhere. But this would be extremely rare to see in hospitals — most of the time, they just kick into resuscitation mode, and follow their normal procedures, which includes cutting the cord, and taking the baby to the table where the oxygen is.

  5. Sharing a story of when the nuchal cord was cut, without attempt to deliver/somersault,

    http://giftedbirthsupport.com/2011/06/01/birth-story-nuchal-cord/

    Cheers,
    K

  6. Is it possible to have a failure to descend from a nuchal cord? My son had a quad-nuchal cord (twice around neck, once around shoulders, and once around and through legs). (My cord was 36″ long!) I fully dilated but after 5 hours of pushing had not progress. He was so entangled, the surgeons couldn’t pull him out of my uterus. He literally had to be unwound to get him out.

    I want to attempt a VBAC this time round, but my current OB (new) suggested he thinks I may have pelvic issues b/c he would still expect to see some progress even with a cord issue. Is this correct?

    • Yes, I have heard of several cases of this. It’s possible that your son was so tangled up in his cord that he could make no progress (having to be unwound to leave the uterus through your abdomen sure sounds like it to me!); although most of the time even with nuchal cords, the baby can make some progress. It sounds to me like your OB is making a convenient excuse so that you won’t try a VBAC, although of course it is possible that you may have pelvic issues as well. It’s also possible that your baby was in an odd position, perhaps due to the entanglement, that made it difficult for him to descend — for example, a face presentation or getting his forehead hung up on your pelvis. However, if that is the case, then a VBAC is likely to be successful. One of my friends had the “stuck forehead” with her first child and ended up with a C-section, but her second was a successful VBAC w/no problem. I don’t remember exactly, but I’m pretty sure she made no progress with pushing, but obviously it wasn’t because of her pelvis!

  7. Thanks for your article. I know this is quite old.
    I just had a c-section with my second baby after being in labor for 3 days – and 6 cm dilated for 2 days with good contractions, but Dr couldn’t feel the baby’s head. When monitoring showed baby was having difficulty – reduced movement / HR going down, etc. (this is after 3 days labor – and i appreciate my obe being so patient) they went for C-section. Umbilical cord was wrapped over her shoulder and under her arm, effectively seatbelting her to the placenta and she couldn’t move.

    I really didn’t want a c-section, but in my case I thank God that one was done and my baby and I are ok.

    If I were to have another child I would definitely go for VBAC. I can’t understand why anyone would want an elective cesarian (it is really painful compared to childbirth and the pain goes on far longer)… but appreciate they can be lifesaving used right.

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