The authors found babies' blood and iron levels were healthier when the cord was clamped later
Delaying clamping of the umbilical cord after birth benefits newborn babies, according to a systematic review published in The Cochrane Library.
In many high income countries, it is standard practice to clamp the umbilical cord connecting mother and baby less than a minute after birth. However, clamping the cord too soon may reduce the amount of blood that passes from mother to baby via the placenta, affecting the baby's iron stores.
On the other hand, delayed cord clamping, which is carried out more than a minute after birth, may also slightly increase the risk of jaundice. The World Health Organization now recommends cord clamping between one and three minutes after birth.
The researchers reviewed data from 15 trials involving a total of 3,911 women and their babies. They looked at outcomes for mothers and outcomes for babies separately, and looked at haemoglobin concentrations as an indicator of healthy blood and iron levels.
While clamping the cord later made no difference to the risk of maternal haemorrhaging, blood loss or haemoglobin levels, babies were healthier in a number of respects.