Latest paper on delayed cord clamping shows no benefit for premature babies

I’ve written before that delayed cord clamping has been found to have no clinical benefits in term infants, but there has been some evidence that it is beneficial for premature babies because it reduces the need for blood transfusions in babies who are likely to develop anemial of prematurity. The latest paper on the topic puts even that claim in doubt.

Delayed Umbilical Cord Clamping in Premature Neonates will appear in the August issue of Obstetrics and Gynecology. The authors explain:

This was a before–after investigation com- paring early umbilical cord clamping with delayed um- bilical cord clamping (45 seconds) in two groups of singleton neonates, very low birth weight (VLBW) (401– 1,500 g) and low birth weight (LBW) (greater than 1,500 g but less than 35 weeks gestation). Neonates were excluded from delayed umbilical cord clamping if they needed immediate major resuscitation. Primary out- comes were provision of delivery room resuscitation, hematocrit, red cell transfusions, and the principle Vermont Oxford Network outcomes.

What did they find?

All neonates had a hematocrit determination (largely peripheral venous) 30 – 60 minutes after birth… VLBW and LBW neonates who underwent delayed umbilical cord clamping had a significantly higher hematocrit, but delayed umbilical cord clamping did not significantly lower the overall NICU red blood cell transfusion rate. Delayed cord clamping was associated with higher mean systolic and diastolic blood pressures in neonates with LBW. Highest measured total bilirubin concentration and use of phototherapy were not significantly different between the early umbilical cord clamping and delayed umbilical cord clamping groups… [W]e observed no significant differences in any of the principle Vermont Oxford Network VLBW morbidities, mor- tality, growth rates, or length of stay …

Delayed cord clamping made no difference in the incidence of chronic lung disease, retinopathy of prematurity, intraventricular hemorrhage, necrotizing enterocolitis, infection, weight gain or length of stay. Obviously, the intitial hematocrit was higher in infants who underwent delayed cord clamping, but it resulted in no appreciable benefits.

The authors do point to one benefit, but fail to realize that it is a direct result of study design, not delayed cord clamping.

… [T]he overall provision of any delivery room resuscitation intervention was signifi- cantly less in the VLBW delayed umbilical cord clamping group (61% compared with 79%, P=.01) but not different between the LBW groups (30% compared with 27%, P=.55). Delayed umbilical cord clamping was associated with higher Apgar scores at 1 minute in VLBW neonates but no significant differ- ences in neonates with LBW….

That was only to be expected because:

… eligible neonates born in the second era did not have delayed umbilical cord clamping because the health care providers felt the neonate needed immediate major resuscitation. These six neonates had a mean postmenstrual age of 31 0/7 weeks, mean birth weight 1,618 g, Apgar score at 1 minute ranged from 0 to 5, Apgar score at 5 minutes ranged from 2 to 7, and all survived…

In other words, infants with the greatest need for resusciation were autonomatically excluded from the deleyed cord clamping group, but not the early cord clamping group. It’s hardly surprising then, that the delayed cord clamping group had fewer infants in need of resuscitation.

The authors conclude:

Delayed umbilical cord clamping can safely be performed in singleton premature neonates and is associated with a higher hematocrit, less delivery room resuscitation, and no significant changes in neonatal morbidities.

Even that tepid endorsement overstates the case. Obviously the hematocrit was initially higher in the delayed cord clamping group; delayed cord clamping inevitably increases the hematocrit initially. Obviously there was less need for resuscitation in the delayed cord clamping group since the infants with the greatest need for resuscitation had been removed from the group.

The bottom line is that delayed cord clamping provided no benefit of any kind.