True Umbilical Cord Knot

True knot of the umbilical cord is a rare condition (up to 1.25% of pregnancies(Ref#1)) with the highest rate occurring in monoamnionic twins. It is difficult to diagnose this with prenatal ultrasound because sonographers are not generally looking for this condition. True knots arise from fetal movements and are more likely to develop during early pregnancy, when relatively more amniotic fluid is present and greater fetal movement occurs. Constriction of a true knot is not common but it may lead to obstruction of the fetal circulation and subsequent intrauterine death. In fact, fetuses with true umbilical knots are at a four-fold increased risk of intrauterine death(Ref#2). It has been reported that true knots are associated with(Ref#1 and #2):
•Advanced maternal age
•Multiparity
•Previous miscarriages
•Obesity
•Prolonged gravidity
•Male fetus
•Long cord
•Maternal anemia
•Maternal chronic hypertension
•Hydramnios
Pulsed wave Doppler spectral analysis can be used to demonstrate a stenotic effect on the umbilical venous blood flow post-stenosis (Ref#3). A pre stenotic dilation of the umbilical vein can also be seen. A cesarean delivery may be considered if a diagnosis of a true cord knot is made.
References
1) Airas U, Heinonen S. Clinical significance of true umbilical knots: a population-based analysis. Am J Perinatol 2002 Apr;19(3):127-32.
2) Hershkovitz R, Silberstein T, Sheiner E, Shoham-Vardi I, Holcberg G, Katz M, Mazor M. Risk factors associated with true knots of the umbilical cord. Eur J Obstet Gynecol Reprod Biol 2001 Sep;98(1):36-9.
3) Gembruch U, Baschat AA. True knot of the umbilical cord: transient constrictive effect to umbilical venous blood flow demonstrated by Doppler sonography. Ultrasound Obstet Gynecol 1996 Jul;8(1):53-6.

Category:

Education

Tags:

• True
• Umbilical
• Cord
• Knot

[sonographers]

Most ultrasound techs don't know how to look for it. Ultrasound is very operator dependent so make sure your doctor specifically request checking for the umbilical cord knot on the requisition. Also, ask the ultrasound clinic that you are planning to book your exam if they know how to check for the umbilical cord knot. Most Women's hospitals have experts who are aware of this condition and it might be wise to have them to check your fetus. Good luck with the rest of your pregnancy!

[rhiannon15767]

my son was born and after my husband cut his cord the nurse found the knot.... truely amazing!!! im so happy to have him!!!! Sorry 2 the mothers that lost there precious little babys its so sad!!! by seeing all the comments it makes me so thankfull for my little one!!! I didn't know how serious it really was till now!!!

[sonographers]

@rhiannon15767 Congratulations on your new arrival! He is a very lucky boy for sure. All the best.

[Bros4life97]

My daughter was born still after 35 1/2 weeks under my heart. She was perfection whose life was ended by the very thing that is suppose to sustain life. She had a true knot in her umbilical cord. Rare doesn't seem rare when you are living without your perfect child. Thank you for trying to raise awareness!!

[sonographers]

@Bros4life97

I am so sorry, your daughter looked perfect. What a nice video memorial! Thank you for sharing.

[laciebaby]

I just lost my baby boy @ 31 weeks 9/6/2010 to a true knot in the umbilical cord. How can I possibly raise awareness on this? These things need to be part of regular scans. I hear these are rare occurences but I've spoken to quite a few women who have had this happen to them as well.

[sonographers]

@laciebaby

Dear laciebaby,

I am very sorry to hear about your baby boy.

We set up ultrasound seminars and conferences in Canada to share new ultrasound techniques and protocols in order to prevent tragedies like what you have experienced. Our next conference is announced at sonographers.ca

We operate with a very small budget and if you would like to support our efforts, you can become one of our sponsors.

[AstronoNurse]

Both of my daughters, born 5 years apart, have been born with true knots in their cords. I have been told this is extremely rare. We were not aware of the knots and both babies were born vaginally, full-term, and healthy. I was not aware about the potential risk until I started doing my own research after their births. I am now pregnant with my third and would like the ultrasound tech to specifically look for this condition. Is this possible, or does it need to be a specific type of scan?

[graverko]

When I was born, I had 3 true knots on my cord. Fortunately, my cord had extremely big diameter, so I was not endangered

[assistant83]

@rhiannon15767

the exact same thing happened with my son... he came 4 weeks early, and to this day I believe that may have been the one thing that saved his life. He is now almost 5 months and I can't imagine not having him here. My thoughts go to those that have lost their little ones.

[saran12ya]

i was 29 weeks when my boy was born still.it happened this 14 sep .... i really cant imagine all has ended so soon... he died of true knot... i ve never heard of it until the same happened to me . the worst part is i did not see, touch and feel baby ..... which is very terrible.... ... thank u for this awareness clip which will help many moms.