Childbirth experts are urging the NHS to reverse the policy it has pursued since the 1960s of clamping and cutting a baby's umbilical cord as soon as it is born, citing mounting evidence that this may leave newborn babies deprived of vital blood from the placenta.
Medical bodies, senior doctors and the National Childbirth Trust (NCT) want maternity staff to stop routinely clamping the cord within seconds of the baby's arrival and instead leave it untouched for anything from 30 seconds to whenever it stops pulsating naturally, usually within two to five minutes.
They believe that infants may be at risk of becoming anaemic by being denied the chance to receive as much as a third of their blood volume from the placenta through the cord. Anaemia can later be associated with brain development and can affect cognitive ability.
At present, delivery of most of the 800,000 babies born each year in the UK is followed by early clamping, after which the cord is cut and the baby is briefly assessed before being returned to its mother. This has been standard procedure across the NHS for about 50 years and is backed by the National Institute for Health and Care Excellence (Nice), which advises the NHS in England what medical practice it should follow.
Nice's current guidance recommends "early clamping and cutting of the cord" to health professionals as a key element of the "active management" of the third stage of labour, just after the birth, unless the woman has had a low-risk pregnancy and specifically requests "physiological management", in which the cord is allowed to stop pulsating and the placenta is delivered naturally.
That advice is under review, as more hospitals are switching from immediate clamping to delaying it, amid growing evidence that early clamping can later lead to a baby developing iron-deficiency anaemia. About 10% of UK toddlers are iron-deficient.
NICE is now reviewing its cord-clamping guidance, which it originally published in 2007. Doctors hope its new advice, due in June 2014, will lead to delayed clamping replacing immediate clamping as the NHS's standard procedure.
Professor Mark Baker, director of Nice's centre for clinical practice, said: "Nice is currently updating its guidelines for the care of women and their babies during childbirth, which includes the timing of cord-clamping, as evidence and intelligence collected during the review process [since its 2007 advice] indicated an update was needed. Our priority is to ensure that mothers and babies get the best possible care."
Prompted by uncertainty among doctors about when to clamp, the National Institute for Health Research has decided to fund the UK's first trial comparing the pros and cons of immediate versus delayed clamping in more than 100 births of babies born before 32 weeks at eight hospitals.
Andrew Gallagher, a consultant paediatrician at the Worcestershire royal hospital in Worcester, which adopted delayed cord-clamping in 2009, said: "Immediate cord-clamping is a harmful practice because it denies the baby the blood from the placenta, and means that later on they are more likely to become iron-deficient. That matters because iron deficiency can cause serious problems. It affects the brain and learning capacity of toddlers ... [who] are going to be slower to learn, for example to speak and to understand.
"It's time for the NHS to sweep away an outdated and potentially harmful and thoughtless practice that we have been doing for decades."
Others have followed suit more recently, such as Liverpool women's hospital – the UK's largest maternity unit with 8,100 births a year – last May and, at the start of 2013, Bradford royal infirmary, which now delays clamping for a minute for full-term babies and 30 seconds for pre-term newborns, who may need medical help.
Cord-clamping was originally introduced to reduce the risk of the mother experiencing serious bleeding after the birth, called postpartum haemorrhage, which can be fatal. But Dr Sam Oddie, a consultant neonatologist with Bradford teaching hospitals NHS trust, said a reappraisal of the evidence for immediate clamping meant many doctors no longer believed it was necessary.
Dr Andrew Weeks, a consultant obstetrician at Liverpool women's hospital and professor of international maternal health at Liverpool University, said immediate clamping as a way of reducing the risk of maternal bleeding became such "an icon or mantra for the safe motherhood movement" that until recently few doctors dared challenge a procedure he believes is ineffective for that purpose.
Belinda Phipps, chief executive of the NCT, said: "When a baby is born, about a third of the baby's blood is still in his/her cord and placenta.
"With no good evidence to support it, it is accepted practice to accelerate the arrival of the placenta with an injection and clamp and cut the cord immediately, depriving the baby of this blood."
The NCT wants the NHS's default position to become leaving the cord for a few minutes, unless the baby's or mother's health necessitates clamping to allow urgent medical intervention. The Royal College of Midwives, which also backs delayed clamping, said midwives should tell mothers-to-be about the pros and cons of both approaches during pregnancy. Some doctors fear delaying clamping can lead to the baby developing jaundice. A growing weight of medical opinion wants the NHS to change to a routine policy of delaying clamping for up to five minutes for babies born at full-term and 30 to 60 seconds for the 10% of babies who are born premature, before 37 weeks.
Influential bodies such as the World Health Organisation now urge delay, while research published by medical journals such as the British Medical Journal (BMJ) and the Cochrane Collaboration has also helped prompt a move away from immediate clamping.
A Swedish study published in the BMJ in 2011, which found that infants who had had delayed cord-clamping at birth had larger than usual iron stores at four months and were less likely to be anaemic, has proved influential.
The Royal College of Obstetricians and Gynaecologists (RCOG) recommends that the umbilical cord should not be clamped earlier than necessary. However, the college backs early clamping in births where the mother is bleeding dangerously or where the baby has been asphyxiated during birth and needs immediate resuscitation.
A spokesman said: "Research has shown that delayed cord-clamping of more than 30 seconds may benefit the newborn in reducing anaemia. It also allows time for the transfusions of placental blood to the newborn, especially in cases of premature birth."q