The benefits of delayed cord clamping: New evidence

Hold on a minute (or three)!

Hold on a minute (or three)!

Something about the cord clamping debate has troubled me for quite some time now. Long after early cord clamping (ECC) was shown to be of no benefit to either mother or baby, and in fact may harm the baby through loss of iron during a critical period of brain development, some in the obstetrics community wanted to see more evidence before endorsing delayed cord clamping (DCC) for healthy term babies. The pro-DCC evidence was theoretical, they claimed; before they agreed to wait a couple of extra minutes to clamp the cord, they wanted hard proof that DCC actually helps babies.

The logic behind this foot-dragging—“We’re not abandoning a pointless practice without a darned good reason,” more or lessescapes me. After all, this isn’t like switching from one way of transplanting hearts to another. DCC doesn’t require new equipment or extensive training, and it’s not a budget-buster, either. You simply wait 2 or 3 minutes to clamp the cord, instead of doing it right at birth. It’s not brain surgery.

Well, there’s finally some solid evidence for the hard-to-convince, pro-ECC crowd. In a recently published randomized clinical trial, a Swedish research team led by Dr. Ola Andersson discovered that a group of healthy children who had been randomized to receive DCC (3 minutes after birth) had significantly better personal-social and fine-motor functioning at 4 years of age than did those who were randomized to receive ECC (< 10 seconds after birth). The effect was more marked in boys than in girls.

Andersson and colleagues checked the children’s iron stores at several points and found that, while DCC babies had more total body iron at 4 months of age, the ECC/DCC difference disappeared by 12 months of age. Looking at neurodevelopment, they found no differences between ECC and DCC babies at 12 months, but by 4 years the DCC children showed significant developmental advantages over the ECC group. It seems like an odd finding: how could a DCC-related “bump” in iron stores in early infancy cause developmental differences at 4 years but not at 12 months?

It likely comes down to an inadequate supply of iron at a critical time in neurodevelopment—those first few months, when many of the brain’s critical neural pathways are established. The resulting delays weren’t detectable with the kind of screening that can be done on a 12-month old, but by 4 years of age more extensive testing could pick it up.

The most important thing about this study is that it was a randomized clinical trial, a study design that can show that “a” is directly connected to “b”. The researchers in this case took two evenly matched groups of infants, randomly assigned them to different treatments (DCC or ECC), and then measured the relevant outcomes (iron stores + developmental differences). While there are some shortcomings to the study—the number of kids involved isn’t huge, for example—the findings fit with what’s currently known about the effects of iron deficiency in early childhood.

This study presents a solid argument in favor of DCC. And if that’s not enough to sway ECC advocates, what is?

More on iron metabolism (and why boys are affected more than girls) in upcoming posts…

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Filed under Cord clamping, Development, Iron deficiency

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