Umbilical Cord Milking – New Research for Non-vigorous Near-term Newborns

When a baby is born, the umbilical cord is clamped and cut to separate the baby from the mother and enable the placenta to be born.

In a normal birth close to term (i.e. around 40 weeks), most healthcare practitioners will practice delayed (or deferred) cord clamping (DCC). During DCC, the cord will remain unclamped for around one to two minutes so that nutrient-rich blood can be naturally transferred from the placenta to the baby.

DCC has been shown to have numerous benefits for near-term, vigorous newborns i.e. those showing good respiratory effort, good muscle tone and a heart rate of less than 100.

What is umbilical cord milking?

Umbilical cord milking or ‘stripping’, is a practice whereby the blood in the umbilical cord is moved along the cord and into the newborn by manual manipulation before the cord is clamped.

It has been a controversial practice but has been suggested as an alternative to delayed cord clamping in situations where DCC is not feasible or is not yielding sufficient blood transfer.

In 2019 doctors warned that cord milking should not be performed on very preterm infants (born before 32 weeks of gestation) as the oxygen-rich and nutrient-loaded blood being pushed into the premature baby may cause ruptures of the underdeveloped small blood vessels in the brain, leading to brain damage and even fatality.

New research into cord milking of non-vigorous infants near term

Now, research carried out by Dr Anup C. Katheria and published in the American Journal of Obstetrics and Gynecology in September 2022, has shown that umbilical cord milking may improve the health outcomes of some newborns, particularly non-vigorous babies – being limp, pale and with minimal breathing – who are born near or at term.

Dr Katheria, a neonatologist at Sharp Mary Birch Hospital for Women and Newborns in San Diego, worked alongside colleagues in the United States, Canada and Poland to carry out the study. The researchers wanted to find out if umbilical cord milking could be proved to be a safe, more effective alternative for non-vigorous babies than immediate cord clamping and cutting to facilitate rapid resuscitation.

The study cohort consisted of more than 16,000 infants born between 35 and 42 weeks at 10 institutions. Of the newborns, 1,730 were included in the study analysis. These non-vigorous infants were then assigned at random to have either immediate cord clamping and cutting or cord milking. The cord milking group underwent a standardised procedure for cord milking.

Study objectives

Dr Katheria said, “The question has always been for the babies who aren’t doing well at birth, who aren’t breathing or are limp or blue, is there something else we could do?”

The research team’s primary objective was to analyse whether cord milking had an effect on admissions to newborn intensive care units (NICU) but no noteworthy difference was seen between the two groups.

However, there were several significant differences between the two groups for the secondary objectives.

• The cord milking group had a higher haemoglobin level than the immediate clamping group.
• Of the cord milking group, 61% required heart and respiratory support, compared to 71% for the clamping group.
• Moderate to severe hypoxic ischemic encephalopathy – low blood oxygen levels in the brain – occurred in 1.5% of the milking group, compared to 3% of the clamping group.

Dr Katheria added that cord milking doesn’t deliver regular blood to newborns, such as that which would be given in a standard blood transfusion. Umbilical cord blood contains billions of stem cells and immune-fighting cells which are so important for newborns.

Research reception

Dr Maria Mascola, lead author of the clinical guidance on cord-cutting for the American College of Obstetricians and Gynecologists, said the study addressed important care issues for newborns.

She notes that the clinical scenario of a non-vigorous near-term infant posed a real challenge for healthcare practitioners: should they delay cutting the umbilical cord because of the known benefits associated with the transfusion of umbilical cord blood or should they immediately move to resuscitate the baby?

Dr Mascola said, “Umbilical cord milking offers a third strategy that has not been previously well-studied in this particular group of newborns.”

While she noted that the study found some important benefits of cord milking, Mascola said that the challenge would be in standardising the practice.

“There are many ways to do it, and it is key to make sure that when it is carried out, it is done so in a specific way that is shown to be safe in studies such as this one.”