Deferred Cord Clamping in Twin Pregnancies

https://youtu.be/RCtUgmqpXA0

Benefit, Risk, or Missed Opportunity?

Bringing a baby into the world is an extraordinary physiological event. In just a few moments, a newborn must transition from relying entirely on the placenta for oxygen and nutrients to breathing independently with its own lungs.

One simple decision made during those first seconds after birth can influence that transition:

When should the umbilical cord be clamped?

Over the past two decades, research has transformed our understanding of this question. For babies born prematurely, delaying cord clamping by at least 60 seconds allows additional blood to flow from the placenta to the baby. This extra placental transfusion improves blood volume, supports the heart during the critical transition after birth, reduces the need for blood transfusions, and even improves survival. Because of this evidence, delayed cord clamping is now recommended for most preterm singleton infants who do not require immediate resuscitation.

But what happens when there are two babies instead of one?

That seemingly simple question becomes surprisingly complicated.

Twins Are Not Just Two Singletons

Not all twin pregnancies are the same.

Some twins develop with two completely separate placentas (dichorionic twins). Others share a single placenta (monochorionic twins), with blood vessels connecting the circulation of both babies.

Those shared blood vessels raise an important concern.

If one twin remains attached to the placenta longer than the other, could blood move from one baby to the other?

Could delayed cord clamping help both babies—or unintentionally benefit one while harming the other?

These uncertainties have led to considerable variation in clinical practice around the world. Some clinicians routinely perform delayed cord clamping in twins, while others avoid it altogether, particularly in monochorionic pregnancies. Yet remarkably, there has never been a clear synthesis of the available evidence.

That question became the motivation for our review.

Looking Beyond the Guidelines

Current international recommendations supporting delayed cord clamping are based largely on studies of singleton infants. Those studies consistently demonstrate important benefits, including reduced mortality before hospital discharge and fewer blood transfusions in preterm infants.

Twin pregnancies, however, have often been excluded from these landmark clinical trials.

As a result, clinicians caring for twins frequently find themselves asking:

"Can I safely apply the same evidence to my patients?"

To answer this question, we reviewed the available literature on delayed cord clamping in twin pregnancies, paying particular attention to monochorionic twins, where concerns regarding shared placental circulation are greatest.

What Did We Learn?

Perhaps the most important finding was not what we found—but what we didn't.

There is no strong evidence that delayed cord clamping is harmful in most twin pregnancies.

There is also no strong evidence proving that it provides the same benefits observed in singleton infants.

Instead, the available literature is dominated by relatively small observational studies and retrospective cohorts. While several studies suggest improved haemoglobin levels, reduced blood transfusion requirements, and shorter NICU stays, the evidence remains inconsistent for major outcomes such as mortality and severe neurological injury.

The greatest uncertainty remains in monochorionic twins.

Because these twins share placental blood vessels, delayed cord clamping may theoretically increase the risk of acute inter-twin transfusion. Whether this occurs frequently enough to influence clinical practice remains unknown. Current evidence is simply insufficient to answer this question with confidence.

A Better Way of Thinking About Cord Clamping

One of the concepts we discuss in this review is physiology-based cord clamping.

Rather than clamping the cord after an arbitrary number of seconds, physiology-based cord clamping focuses on when the baby has successfully transitioned to breathing.

Once the lungs begin to function, blood flow through the lungs increases and naturally replaces the blood that had previously returned from the placenta. Clamping the cord after this physiological transition may provide a smoother cardiovascular adaptation than simply waiting a fixed amount of time.

Although this concept is supported by strong physiological evidence, studies evaluating physiology-based cord clamping in twins remain extremely limited.

Where Do We Go From Here?

This review does not conclude that delayed cord clamping should be avoided in twins.

Nor does it suggest that all twins should automatically receive delayed cord clamping.

Instead, it highlights an important evidence gap.

Twins—particularly monochorionic twins—deserve the same high-quality clinical research that transformed care for singleton infants.

Future studies should evaluate not only short-term outcomes such as transfusion requirements and haemodynamic stability but also long-term neurodevelopment. Individual participant data meta-analyses and adequately powered multicentre clinical trials will be essential to answer these questions.

Why This Matters

Every advance in neonatal medicine begins with a question.

For singleton babies, delayed cord clamping has changed practice around the world because researchers asked whether waiting just a little longer before clamping the cord could improve outcomes.

Now, we must ask the same question for twins.

Until stronger evidence becomes available, cord management should be individualized, taking into account chorionicity, the condition of each infant, and the clinical circumstances at birth. At the same time, we should continue generating the evidence needed to ensure that every baby—whether born alone or with a twin—receives the safest and most effective care possible.

Take-Home Message

🩸 Delayed cord clamping clearly benefits preterm singleton infants.

👶👶 Twin pregnancies present unique physiological challenges, particularly when twins share a placenta.

🔬 Current evidence is encouraging but remains insufficient—especially for monochorionic twins—highlighting the need for high-quality clinical trials before definitive recommendations can be made.

Research4Babies

Advancing neonatal research. Sharing knowledge. Improving newborn lives.

Reference

Deferred cord clamping in twin pregnancies: benefit, risk, or missed opportunity? A narrative review

Aimann Surak, Graeme Polglase, Georg M. Schmölzer