There is new evidence that delaying cutting or clamping the umbilical cord may be good for a baby. 

It’s common practice to clamp the umbilical cord quickly after birth. But this stops the flow of nutrient-rich blood from the placenta.

A new study has found that delaying cord clamping after birth by five minutes can have positive effects on the brain structure of infants. The study, published in The Journal of Pediatrics, was conducted by researchers at the University of Rhode Island and Brown University, and examined 73 healthy babies.

The researchers divided the babies into two groups as they were born. One group had their umbilical cords clamped after a five-minute delay, while the other group had the cords clamped quickly, within 20 seconds. Both groups were held on their mothers’ bare skin while the clamping took place.

When the babies were four months old, they were given a series of tests: a magnetic resonance imaging scan (MRI) of their brains, a test of their brain development, and a blood test that checked their ferritin levels. Ferritin tests show how much iron is currently circulating in your blood.

The babies who had their cords clamped later showed more positive developments. For one, they had higher levels of ferritin in their blood than the babies who had been clamped rapidly after birth. For another, their MRIs showed that their brains had more of a substance called myelin. 

Myelin is a fatty substance that insulates nerves and helps them communicate efficiently. It makes up a large portion of the “white matter” of our brains, and works to protect our “grey matter,” or neural cells.