When I was a bright-eyed and bushy-tailed student midwife I was awarded with a certificate and a box of chocolates. My achievement was collecting the most cord blood in the hospital. At that time the Local Health District was trialing a cord blood bank. The collected stem cells were to be used for treating leukemia and for research. Every woman birthing in the hospital was asked to donate cord blood for the good cause, and many generously agreed. I was exceptionally good at collecting the blood. This post is a small attempt to repent for my sins.
In recent years cord blood collection and storage has become popular, particularly in the private sector. Cord blood contains magical stem cells, and the idea is that if your baby becomes ill in the future you may be able to use these cells as treatment. My concern with cord blood banking is the inadequate and misleading information given to parents. This misinformation raises both ethical and legal issues. The procedure involved in collecting cord blood is sold as ‘simple, safe and effective’. When it comes to decision making about cord blood only three options are presented: keep it (pay for storage), donate it (to a public initiative) or throw it away. What about letting it finish its journey through the umbilical cord and into the baby who owns it?
Even the term ‘cord blood’ is misleading – blood is merely collected via the cord. When adults give blood we don’t give ‘arm’ blood – we give our blood via our arm. In addition, the promotional materials talk about collecting ‘blood from the placenta’ without acknowledging that the baby/placenta are one blood circulation unit. After birth the blood from the placenta transfers to the baby, assisting transition to breathing. Knowledge about the short term and long term health benefits of allowing placental circulation to complete the job is becoming widespread. See this post for an overview of the physiology of newborn transition to breathing, and for links about the health benefits of full blood volume for babies. With further research one of the long term benefits may actually turn out to be protection against some of the illnesses stem cells are being collected to treat.
Parents need to be informed that cord blood collection requires premature cord clamping, and that the blood being collected belongs to their baby.
In the procedure guide for collection there is no mention of when to clamp the cord. This may lead parents to believe they can delay cord clamping and still collect cord blood. This is not an option. After the placenta has finished transferring blood to the baby it is difficult to collect even the few mls needed for blood group testing (Rh neg). The large umbilical vessels are empty and by the time the placenta has been birthed, the blood in the small vessels has begun to clot. You have to faff about trying to scavenge enough un-clotted blood from the small vessels covering the placenta. The minimum required for cord blood collection is 45mls. Take a look at the photograph of a placenta that finished its circulation before being clamped. If you reckon you could get 45mls out of that, you deserve a certificate and some chocolates.
This diagram from the British Medical Journal shows the transfer of blood volume from placenta to baby after birth
Pediatric guidelines state that ‘blood draws in infants and children should not exceed 5% of the total blood volume in any 24 hour period’. A 3.6kg newborn has a blood volume of around 280mls – so the maximum blood draw would be 14mls. How come these rules don’t apply immediately following birth? The collection bag for cord blood holds 250mls (35mls already taken up with anticoagulant fluid). The minimum amount of blood acceptable for collection is 45mls, and the maximum possible is 215mls. During my vampire-midwife days I reckon I generally filled at least half of the bag – so around 90mls. In the photograph at the top of this post the bag looks more than half full. This amount of blood represents a significant proportion of the newborns blood volume.
I wonder how many parents would consent to someone coming onto the postnatal ward and sticking a needle into their baby to collect around a third of their blood volume? Cord blood collection is the same thing… only the needle is in the umbilical cord rather than the baby.