Updated: April 2022
To get this blog going I decided to write about a slight obsession of mine: The fear of, and routine ‘management’ of nuchal cords at birth (umbilical cord around the neck). I have written and presented about this topic and have bored the pants off many a person who has made the mistake of mentioning the subject. So, despite telling my colleagues that I had put away my ‘nuchal cord’ soap box I am bringing it out to launch this blog. The content of this post is based on part of a literature review I carried out for my PhD thesis. If you are interested in finding out more you can read the literature review in my thesis. I have also written a couple of journal articles on the topic: nuchal cords: think before you check and nuchal cords: sharing the evidence with parents; and had my work cited in guidelines and textbooks.
Why and how babies end up wearing their cord around their neck
The presence of a nuchal cord is a very common occurrence during birth. Up to 30% of babies are born with their umbilical cord around their neck (Mercer et al. 2010). How and when it ends up there will be different for individual babies. Interestingly, it is more common with male babies (Martin et al. 2005) – perhaps because they are more likely to have longer cords (Rogers et al. 2003). It also becomes more common with increasing gestation – I suppose there is more time to get wrapped the cord. If a nuchal cord does not occur in pregnancy it can occur during labour. As the baby moves through the pelvis they rotate and can wind the cord around their neck. See this post to see how rotation works.
A versatile scapegoat
The nuchal cord has become the perfect scapegoat because it lays blame with the mother/baby rather than the care provider/system. This has resulted in fear about nuchal cords becoming embedded within our culture. Whenever I read a story about an unexpected birth outside of hospital it often involves a nuchal cord. The story being about how lucky the baby was to survive the dangers of a nuchal cord away from the experts who can manage such a complication. In addition, I have heard too many birth stories where complications were unfairly blamed on the presence of a nuchal cord.
Before I tackle some of the myths—some quick anatomy and physiology: The cord is covered in Wharton’s jelly and coiled like a telephone wire. This protects the 3 blood vessels from the kind of stretch and compression involved in being attached to a mobile baby. The umbilical cord is also long enough (average 55cm) to be comfortably wrapped around the neck with plenty of left over length. Essentially, the umbilical cord is ‘designed’ to be worn around the neck (and body) without causing a problem.
Research has found that a nuchal cord is not associated with morbidity or mortality for the baby during pregnancy (Carey & Rayburn 2000; Aksoy 2003; Clapp III et al. 2003; Gonzalez-Quintero et al. 2004). Unfortunately, some babies die before labour begins, and there is often no known reason, which can add to the devastation for the family. When these babies are born they are often found to have the cord around their neck (like a 3rd of all babies). Although I can understand the need to find a reason and to pick the obvious, I don’t think this is helpful in the longer term. Parents need honest answers about the loss of their baby, even if the answer is ‘we don’t know’.
There is no evidence that a nuchal cord during labour causes short-term or long-term mortality or morbidity (Masad et al. 2019; Tagliaferri et al. 2019). There is no indication to undergo a c-section if a nuchal cord is identified antenatally. The baby is not ‘held up’ by the cord because the whole package – fundus (top of the uterus), placenta and cord are all moving down together (see diagram). The uterus ‘shrinks’ down (contracts) moving the baby downwards, along with their attached placenta and cord. In fact, the space between the baby’s neck and the placenta is shorter at the end of labour because the baby is more scrunched up. However, when a c-section is performed for ‘fetal distress’ or ‘lack of progress’ during labour, the presence of a nuchal cord is often used as the reason… “your baby was stressed because the cord was around his neck” or “…the cord was stopping her from moving down”. The cord is unlikely to have had anything to do with any stress or lack of progress. Most likely, other interventions carried out during labour led to the end scenario (in particular, the use of syntocinon).
Birth (the last bit of labour)
The nuchal cord remains around the baby’s neck as his head moves out of the uterus and through the vagina. Usually the cord remains loose as there is lots of ‘give’ in it, and it requires less length than at the end of pregnancy (see diagram). A loose nuchal cord does not cause any problems. Blood continues to flow through the vessels just as it did during pregnancy and labour.
Very occasionally, a cord becomes stretched and tight during this last bit of labour – as the head is born. Either there is not enough ‘give’, or the cord is trapped against the pelvis by the baby’s body. This may happen with a shorter than average cord that is wrapped around the neck a number of times. However, the baby is not ‘strangled’ because he/she is not breathing oxygen – oxygen is provided by the cord, not their airway. Whilst the cord is stretched and compressed the blood vessels transfer less blood (but still some). This may result in short-term hypoxia (reduced oxygen supply) which resolves once the cord is loosened after birth and full blood flow resumes. These babies may arrive a little compromised but quickly recover – if the cord is left alone. Unfortunately, the way in which the situation is managed (see below) can create further problems. The resulting need for resuscitation is then blamed on the nuchal cord rather than what was done to it by the care provider.
Risks associated with clamping and cutting a tight nuchal cord
Once the cord is clamped, blood flow between the baby and placenta ceases, reducing the baby’s blood volume and oxygen supply. This makes resuscitation more necessary and difficult once the baby is born. Any delay in the birth of the baby (eg. shoulder dystocia) will further increase the risk of hypoxia. While waiting to be born, the baby now has NO blood supply rather than a limited one that can be re-established after birth. There have been successful malpractice actions against obstetricians in the US who cut nuchal cords prior to shoulder dystocia (Iffy et al. 2001).
One study (Sadan et al. 2007) found that neither cutting nor leaving a nuchal cord adversely affected the outcome for babies. However, they did not look at tight nuchal cords, and the cords were cut after the baby’s shoulder had birthed. The damaging effects of cutting a nuchal cord are becoming commonly understood in medicine and midwifery. A policy of keeping a nuchal cord intact has been found to improve outcomes for babies (Parr et al. 2014).
For a baby with a tight nuchal cord the worst thing you can do is clamp and cut!
Risks associated with pulling and looping a loose nuchal cord
A far more common practice is pulling and looping a loose nuchal cord. Most care providers do this and I was taught to do this when I trained. However, handling the cord stimulates the umbilical arteries to vasoconstrict, reducing blood flow. Loosening the cord will usually involve some traction which can risk tearing the cord and subsequent bleeding (from the baby), or partial detachment of the placenta. As a student midwife, I snapped a cord while looping it over the baby’s head. Luckily, my mentor clamped the ends quickly, but not before I got blood sprayed in my eyes! I later discovered that babies can be born with the cord around their neck. They either birth through the loop, or they come out with it still wrapped.
Checking for a nuchal cord
So, if you are not going to cut or loop a nuchal cord what’s the point in digging about to see if it is there? Checking for a cord interferes with the physiological process of birth. It also reinforces the notion that this is a birth complication that endangers the baby, rather than a common situation. Telling the woman to stop pushing and putting your fingers into her vagina can be disempowering and painful. There are also consent issues – how many care providers gain consent before this procedure?
- Talk to parents before birth about the possibility and normalcy of a nuchal cord (a third of all babies have a nuchal cord at birth)
- During birth DO NOTHING.
- IF the cord is preventing the baby descending once the head is born (extremely rare) use the ‘somersault technique’ see photos in this article by Mercer et al. (2010) or this movie.
- Once the baby is born, unwrap the cord (the mother/family can do this).
- If the baby is compromised at birth encourage the parents to talk to their baby and touch him whilst the placental circulation re-establishes the normal blood volume and oxygen for the baby. If the baby requires resuscitation, do it with the cord intact.
The baby in the photo at the top of this post was born at home into water. His cord was tightly around his neck twice. The midwife is unwinding the cord whilst bringing him to the surface and into his mother’s arms. He took around 30 seconds to start breathing whilst his placental circulation re-established his blood volume and oxygenated him. His father gently blew on his face and he took his first gasp – resuscitated by his placenta and his father.
Here is an amazing film of a baby with a multiple nuchal cord beautifully managed by his mother:
You can also watch a mother unwrap a nuchal cord during a water birth here.