Delayed umbilical cord clamping: research into the health benefits to babies

Premature birth is one of the leading causes of death worldwide for children under the age of five. After birth, the baby's umbilical cord is clamped and cut, separating the baby from the placenta. There is now evidence that babies benefit from a short wait before clamping the cord, allowing time for extra blood to flow from the placenta into the baby. This is called deferred (or delayed) cord clamping.

Professor Heike Rabe from the Brighton and Sussex Medical School conducted research into the beneficial health effects of delaying clamping the umbilical cord and her research demonstrated that delayed cord clamping in preterm babies significantly reduces deaths of babies in hospital.

Find out more about the work of Professor Heike Rabe at BSMS

Understanding the health benefits of deferred (or delayed) cord clamping

Early clamping of the umbilical cord has traditionally been standard practice, allowing preterm babies to be transferred quickly to neonatal care. Yet, waiting for 30 seconds to three or more minutes before clamping the cord allows vital placental transfusion which may improve the baby’s health. In 2012, delayed cord clamping was highlighted as a priority review topic by the Cochrane Pregnancy and Childbirth Group, which includes consumer organisations, professional bodies, guideline developers and policy makers. Professor Heike Rabe led the Cochrane Review that addressed the need for research-based evidence on the effects of delayed versus early cord clamping at preterm birth on babies’ health.

Heike Rabe’s evidence on delayed cord clamping has been the key driver of change in all 12 maternity and neonatal units in the West and South West of England, leading to their delayed cord clamping rate rising from 30 per cent to 85 per cent of their preterm births in one year.

Using evidence from 15 trials involving more than 700 mother and baby pairs, it was proved that delaying cord clamping for 30 to 120 seconds led to preterm health benefits such as a reduced need for blood transfusion and risk of brain haemorrhage. In 2019, Cochrane Pregnancy and Childbirth Group commissioned Heike Rabe to update the 2012 review to include guidance on ways to implement delayed cord clamping at preterm birth while providing essential neonatal care. This updated review included 40 studies undertaken in 19 countries providing data on 4,884 babies and their mothers. The review found that preterm babies had a 27 per cent increase in survival rate if cord clamping is delayed at birth and a significant reduction in brain haemorrhages. This review was published by the Cochrane Pregnancy and Childbirth Review Group, which is highly influential in informing clinical guidelines on a national and international level, particularly in neonatology.

Placental blood transfer and delayed umbilical cord clamping

With guidelines recommending delaying clamping of the cord at birth as part of routine care for infants, more studies emerged on the best way to improve the redistribution of placental blood into the baby at birth. The National Institute for Health Research for Patients' Benefit project led by Rabe in collaboration with Professor Ayers at City University, London compared the neurodevelopmental outcome at two- and three-and-a-half years in preterm babies benefiting from delayed cord clamping and cord milking, another alternative to increase placental blood transfer. In this first follow-up study looking at the outcomes of both methods to increase placental transfusion on preterm babies over their first three-and-a-half years, Heike Rabe and colleagues showed that neither method produced any long-term adverse effect on developmental outcome at their development at these early years’ checks.

Heike Rabe’s Cochrane Review on the optimal timing of the umbilical cord clamping has been instrumental in changing UK and international policy (EU, Canada and USA) on the use of delayed cord clamping in preterm births. In doing so, it has led to a shift in the understanding and acceptance on the importance and benefit of delayed cord clamping with these results filtering through to a shift in practice to realise these benefits.

Recommendations from the review have contributed to 17 national and international guidelines, including the World Health Organisation Care of the Newborn Infant and National Institute for Health and Care Excellence Preterm Labour and Birth guidelines, and the British Association of Perinatal Medicine Optimal Cord Management Toolkit. The Toolkit informs a national rollout of this practice to all maternity and neonatal units in England. Heike Rabe was part of a four-nation team of obstetricians, midwives and neonatologists, together with parent representation leading on the development of the Toolkit. Its implementation in maternity and neonatal units across NHS England will be supported throughout England by the Maternity and Neonatal Safety Improvement Programme. The research has changed health practitioners’ attitudes towards delayed cord clamping, increasing its adoption in clinical practice in the UK, the USA and many other countries.