Delaying cord clamping for six minutes is safe

New research has added to our knowledge about delaying cord clamping. We know now that it is safe to wait 6 minutes after birth, even when an oxytocic drug is given to assist with the birth of the placenta.

Waiting, which is sometimes called delayed cord clamping or optimal cord clamping, means that the baby has the chance to get all the blood that they need from the placenta before the supply is cut off.

We have known for many years that it is better to wait than to interfere, but it is taking a while for things to change in some areas of the world.

This is because, in recent decades, there has been a tendency to interfere with birth. (I explain why in this book.)

But a new research study further confirms that there are advantages to delaying cord clamping.

Here’s what I wrote about the study in my Birth Information Update.


Delaying cord clamping for six minutes is safe

You might already know that I have a long-held interest in the birth of the placenta and in how optimal cord clamping can promote good health in babies by ensuring they are able to get the blood they need before someone cuts off the supply. If so, you’ll not be surprised to discover how pleased I was to see a paper by Winkler et al (2022). This research looks beyond the three-minute cut-off point for which we currently have safety data.

As they explain, we already know that, “Delaying cord clamping (CC) for 3-5 minutes reduces iron deficiency and improves neurodevelopment.” (Winkler et al 2022).

However, “Data on the effects of CC beyond 3 minutes in relation to short-term neonatal outcomes and maternal risk of postpartum hemorrhage are scarce.” (Winkler et al 2022).


The research

So they carried out an observational cohort study, in Sweden. They looked at 904 woman/baby dyads who had vaginal births. Cord clamping was performed at a median time of 6 minutes, though the range of timings was wide. Some babies’ cords were clamped immediately, and in at least one case the cord was left intact until 23 minutes after birth.

In a nutshell, the research showed that it is safe to wait at least 6 minutes before clamping the cord. And it didn’t matter whether oxytocin was given before or after cord clamping. This latter finding is important, because it means that optimal cord clamping is a safe option even for those who want an actively managed third stage and/or where it is not considered safe to wait too long before giving an oxytocic drug.


The findings

Here’s what the researchers found:

“This large prospective observational study of 904 mother-infant dyads shows an absence of correlation between delayed CC beyond 3 minutes and negative short-term neonatal outcomes, including increased risk of phototherapy, in term and late-preterm infants.” (Winkler et al 2022).

One aspect of the findings was particularly interesting, especially given what I wrote above about giving oxytocin for the birth of the placenta:

“Furthermore, a negative correlation between CC time and postpartum blood loss was observed. The administration of oxytocin before or after CC was not associated with any differences in postpartum blood loss or neonatal morbidity.” (Winkler et al 2022).


Less blood loss and no increased risk of jaundice

The researchers discuss the fact that less blood loss was observed in those who had longer delays before cord clamping, as there may be a number of reasons that would explain this. As always, I recommend reading the study in full. It’s freely available here.

They also highlight the finding that there was no increase in phototherapy. That’s important because the theoretical (and now disproven) risk of increased jaundice (which is treated by phototherapy) is cited by some organisations (for instance the American College of Obstetricians and Gynecologists) and reviewers as a reason to clamp and cut the cord early. Some of the evidence previously used to support this theory has been at high risk of bias, so the current study is particularly useful in showing that jaundice is not more likely if the cord is left for longer before clamping.


The conclusion

The study conclusion is clear:

“Umbilical CC times beyond 3 minutes in vaginal deliveries were not associated with negative short-term outcomes in newborns and were associated with a smaller maternal postpartum blood loss. Although CC time as long as 6 minutes could be considered as safe, further research is needed to decide the optimal timing.” (Winkler et al 2022).

So this is really helpful, especially for those who want to challenge old practices and provide colleagues with evidence which supports waiting longer.


But wait? Why only six minutes?

I also want to add a word about the researchers’ statement that “up to 6 minutes could be considered safe” and that “further research is needed to decide the optimal timing.”

I know that some people may be rolling their eyes at the fact that the onus is put on those who tend to trust nature and female physiology until proven otherwise to ‘prove’ the safety of physiology when it is obstetric and paediatric interference that is the recent innovation here.

Yes, I agree that the burden of proof should be upon those who want to impose intervention. But that’s not the reality of the world we live in. In order to get papers into the journals read by those who need to read such papers, researchers may need to take account of the context, language and terms of reference of the dominant biomedical approach.

In this case, it’s working. Each paper on this topic takes us a bit further away from the routine interference that so many mums and babies are unnecessarily and sometimes harmfully subjected to in this area, and for that I am immensely grateful to the researchers who run studies like this one.


Want to know more?

If you’d like to know more about this and related areas, I have a whole information hub offering blog posts and articles related to the birth of the placenta, which includes optimal cord clamping.

I’ve also co-authored a book which helps women and families to better understand the evidence, so you can make the decisions that are right for you.

You can see the research study that I’m talking about here: Cord clamping beyond 3 minutes: Neonatal short-term outcomes and maternal postpartum hemorrhage.

And if you’d like to get regular updates on birth-related research and thinking, sign up to my newsletter so that, like thousands of other people, you can get my research updates early, and straight to your email inbox.


Winkler A, Isacson M, Gustafsson A et al (2022). Cord clamping beyond 3 minutes: Neonatal short-term outcomes and maternal postpartum hemorrhage. Birth: Issues in Perinatal Care.

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