In the biggest study done on the rates of cord avulsion (in this case defined as the cord snapping just after birth), it was found that it was slightly more common for the cord to snap during a waterbirth compared to a land birth. Looking at 17,530 waterbirths, and 17,530 land births, Bovbjerg et al. 2021 found that the rate of cord avulsion at water birth was 4.1 incidents per 1,000 waterbirths, versus 1.3 incidents per 1,000 land births.
This is often cited as a risk of waterbirth. In fact, it appears to be a risk of insufficient training in waterbirth care rather than a risk of waterbirth itself, and can be mitigated by understanding the cause, and changing practice.
Why might the cord snap?
Some babies have umbilical cords which have developed with problems that make them less strong, so more likely to break. However, even taking this into account, we see more cases of “typical” cords snapping during waterbirth than land birth. Why might this be?
By far the most common reason for the cord to snap is the midwife or doctor pulling the baby out of the water too quickly, putting pressure on the cord and snapping it. This is more likely if the cord is unusually short. The fear of having the baby under water too long, and therefore pulling them up too quickly, is the explanation for almost all snapped cords. For this reason, changes of practice will remove this risk.
What can I do to improve my practice?
1) Understand that babies have a range of protections that stop them from inhaling water during a waterbirth. During labour, a baby’s practice breathing stops, and the instinct to not inhale liquids is triggered. This will only be over-ridden by an extremely compromised, oxygen-starved baby who is probably unconscious and who may gasp at birth, but it is very unlikely that such an unwell baby will not be recognised before they are born.
2) Of course it’s important for babies to be brought out of the water without undue delay, but this can still be a gentle movement, with great care taken to ensure that the cord isn’t pulled. Even better, supporting mothers and birthing parents to bring their own baby to the surface means that they have the feedback within their own body to not pull on and snap the cord.
3) If the cord is too short for the baby to not be brought to the surface, don’t panic, just ask the mother to stand, and if possible lower the water level.
In summary: While cord avulsion is slightly more common in waterbirth, it is still very rare, and some simple changes in practice will most likely stop it from happening any more often than in land births.