Delayed cord clamping: why cut the cord as late as possible?

During pregnancy, the umbilical cord connects the foetus to the placenta. The placenta transports nutrients and oxygen from the mother to her baby. After birth, the placenta remains attached to its umbilical cord, while blood that is very rich in nutrients stays in the cord and in the placenta.

At birth, blood continues to flow through the cord, delivering oxygen to the baby while breathing through the lungs becomes established. As long as the cord remains in place, the baby receives 19 ml/kg, which is more than 20% of its blood volume at birth [1]! Three-quarters of this transfusion occurs during the first minute after birth.

Placental transfusion helps to drain the blood remaining in the placenta, which may assist the placenta in separating from the uterus and thereby reduce overall blood loss at birth for the mother.

Until now, standard practice was to cut the cord immediately after birth. Delayed clamping means that doctors do not cut the cord straight away, but wait a little for the baby to receive blood from the cord and placenta.

According to the WHO, clamping is generally considered early if it is performed within the first 60 seconds after birth, whereas it is considered delayed when more than one minute has passed after birth, or when one waits for the pulsations inside the cord to stop before clamping.

It reduces the risk of anaemia

Did you know that a full-term baby can have up to 1/3 of their blood in the placenta before labour begins?

For full-term babies, delayed cord clamping increases the baby's blood volume and iron stores. The baby can thus receive iron reserves for 3 months! A 2013 review showed that children who had clamping after 1 minute of life had higher iron levels at 2 and 6 months than the others [2].

Iron is very important for babies' cognitive and social development [3]. A Swedish study of 4-year-old children shows that those who had delayed cord clamping 3 minutes after birth had better fine motor and social skills than those whose cord was clamped 10 seconds after birth [4].

It reduces the risk of complications in premature babies

Delayed cord clamping appears to be even more beneficial in premature babies. Babies born prematurely are indeed at greater risk of developing complications, and this extra boost has been shown in studies to reduce those risks: lower risk of anaemia, lower risk of necrotising enterocolitis (a severe complication affecting the newborn's intestines) and of intraventricular haemorrhage (a bleed in the baby's brain that can leave lifelong neurological consequences) [5].

The only exception would be babies with intrauterine growth restriction, who have a higher risk of oxygen deprivation following polycythaemia (= a high number of cells in the blood) [6].

The main concern with delayed cord clamping is that the additional blood volume could result in jaundice, but as babies are monitored for jaundice, this is a complication that is easily diagnosed and treated (by placing the baby under a light to break down the excess bilirubin in the blood).

Scientific studies have furthermore shown that whilst delayed cord clamping does increase bilirubin concentrations, it does not increase the number of jaundice cases requiring treatment [8].

What are the contraindications to delayed cord clamping? 

Doctors advise against delayed cord clamping for women with abnormal placentas, women who have previously experienced postpartum haemorrhage, and of course in cases where babies are born with an immediate need for medical care.

However, studies have shown that early cord clamping had no effect on placental retention or postpartum haemorrhage [9]. And that even in critically ill babies, it was sometimes worth waiting 30 seconds before clamping and providing care "on the spot" [10] (even though this is often very complicated from a practical standpoint, particularly when the cord is short).

There would be no additional risk of waiting a little before clamping the cord for the baby or the mother during a caesarean section. The teams simply need to ensure the baby is kept warm during those few minutes.

And what about lotus placenta?

There are practices involving even later cord clamping.

In a "lotus birth", the cord is not cut: it remains attached until it separates on its own. Scientifically, the effects of even later clamping are not clear, as the bulk of the transfusion would appear to occur during the first 3 minutes [11].

Of course, lotus birth practice goes beyond the simple aspect of transfusion: its aim is to allow the baby not to be "startled", to gradually leave this first bond with their mother, and to remain in their "cocoon" in order to land gently.

However, studies have reported cases of bacterial infection of the placenta, which could then "travel up" to the baby [12] [13], cord infection (known as omphalitis, which is fatal in children in 15% of cases) [14], and risks of clot formation [15]. This is therefore something to discuss with your midwife or a healthcare professional!

Should the placenta be positioned in a certain way relative to the baby?

According to certain beliefs, delayed cord clamping requires the newborn to be positioned with the placenta in what is called a "dependent" position. No reliable study has demonstrated that raising or lowering the baby between birth and cord clamping has any impact on the health of the baby or the mother. Recent studies have shown that this position does not affect the volume of blood transferred, particularly when the baby is simply held skin-to-skin against the mother's chest [16].

Les bénéfices du clampage tardif de cordon sont nombreux (notamment avec l’augmentation du fer), n’hésitez pas à en parler à votre médecin, sage-femme et doula avant la naissance.