Birth Myths & Facts - Nuchal cords
Say what? Nuchal cord..... Most of my birthy friends will know what this is (I hope.... I did attend a birth recently where the midwife didn't know what 'en caul' was, scary I know!) but for those who don't here is the "official" definition:
A nuchal cord (/ˈnʲu.kəl/ occurs when the umbilical cord becomes wrapped around the fetal neck 360 degrees. Nuchal cords are common, with prevalence rates of 6% to 37%. Up to half of nuchal cords resolve before delivery.
How does a baby wind up tangled in their cord?
If you're thinking this then the chances are you've never been pregnant with an active baby before...babies move around...alot! So it makes sense that some will get tangled in their cord and wind up with it wrapped around their neck or their belly.
In most cases, the baby is able to unwrap themselves from their tangle as the cord's structure allows for the cord to be easily slipped over and around the baby and has built in protections to prevent it from being knotted or tangled permanently.
As the baby grows, obviously their space inside the womb is restricted and if the cord is already wrapped around their neck it is more likely that it will stay that way and the baby will be delivered with a nuchal cord.
Anatomy of the umbilical cord
The umbilical cord is encased in a special membrane that aids in the exchange of fluids. Inside the cord are two arteries and a vein, their jobs are to funnel oxygen and nutrition to the baby from the placenta and de-oxygenated, nutrient depleted blood from the baby back to the placenta.
Around these vessels, is a substance called Wharton's Jelly. This protects the blood vessels from being crushed by being twisted and knotted, the jelly acts as a cushion to keep the vessels safe.
The amniotic fluid within the sac also acts as protection from the cord being compressed; the cord floats in the fluid rather than being pressed up against the wall of the womb and potentially squished by the baby. (Side note: this is why it was dangerous when my waters broke prematurely with our second baby, Tommy, with no amniotic fluid left and still 20 weeks to develop, the risk of cord compression and compression to Tommy himself was real leading to increased risk of cerebral palsy due to lack of oxygen and a condition called Potter Syndrome which describes a certain set of features in the baby which are caused by the baby being under pressure from the lack of fluid in the womb.)
A cord with little Wharton's Jelly is at increased risk of cord compression due to the lack of protection provided from the jelly, however, the amniotic fluid comes into play here and helps to protect the blood vessels from compression from the outside. It's a beautiful medley of team work!
How amazing are our bodies...seriously.
The risks...
Despite nuchal cords being quite common, there is still a lot of fear instilling going on from health providers when it is identified that a nuchal cord is present. As with anything, there are real risks, however we are often led to believe that these risks are more prevalent than they actually are. For how common nuchal cords are, the risk of perinatal death is quite slim.
Studies have shown that despite the rate of nuchal cords being present at birth, the risk of hypoxia was low. Studies also show that there are two types of nuchal cords, tight and loose nuchal cords, with tight nuchal cords being more dangerous than loose nuchal cords but also being less prevalent making tight nuchal cords rare. In a study of 2530 women 23.5% had a nuchal cord and of those only 1.9% had a tight nuchal cord.
Only 4.2% of babies with a nuchal cord required resuscitation and 3.2% needed to be admitted to NICU.
Another study found that whilst babies in their study who presented with nuchal cords were born with Apgar scores of less than 7, that nuchal cords were not a major cause of fetal asphyxia.
What I found interesting from this study was that whilst babies presenting with a tight nuchal cord had lower APGAR scores at 1 minute, that by the 5 minute APGAR score their results had improved significantly and the nuchal cord had no bearing on these results which suggests that the effects of a nuchal cord on a baby's health are transient and not long lasting.
This is where the benefits of delayed cord clamping come in, especially for babies who have been deemed to be in 'fetal distress' during labour or who have a tight nuchal cord during birth. Leaving the baby attached to their placenta after birth allows them to receive all of the blood from the placenta, and in this blood is increased oxygen. So whilst your baby may already be taking breaths, the benefits of your baby receiving their full placental blood and stem cells is almost immeasurable (...but it is measurable and I will be writing a blog about this too!).
Unfortunately though, the babies who need their full placental blood most are the ones who are denied it. They are whisked off to be suctioned and taken to NICU, which in theory can all be done whilst they're attached to their placenta but it never plays out that way.
Thankfully, as more research is done into nuchal cords, and as more babies are delivered safely and without complication with nuchal cords being present, attitudes towards nuchal cords and the treatment of them is changing. This is where it pays for you to research into your chosen healthcare provider for your birth - ask what their opinions are on nuchal cords and how they choose to manage them, what your options are if this were to arise and if you're not comfortable with their method of management then look elsewhere.
It is your birth and the choice is in your hands. You can find a provider who will manage your birth and pregnancy in a way in which makes you feel safe, supported and comfortable that what they are doing is evidence based and not based in fear.
