In cases of very preterm birth, waiting at least 2 minutes to clamp the umbilical cord, coupled with immediate neonatal care with the cord intact, improved outcomes, according to a UK multicenter study.
The two major outcome measures were intraventricular hemorrhage (IVH) and infant death before hospital discharge.
Participants were 261 women expected to deliver a live birth before 32 weeks and their 276 babies.
The women were equally randomized to one of two policies for cord clamping and immediate neonatal care: clamping after at least 2 minutes and immediate neonatal care with the cord intact, or clamping within 20 seconds and immediate neonatal care after clamping.
“Waiting at least 2 minutes before clamping was based on a balance between waiting until umbilical flow ceased (which may take 3 to 5 minutes, or even longer) and what was acceptable to clinicians,” the authors wrote.
The mean age of women in the delayed clamping group was 30.3 years versus 29.2 years in the immediate clamping group.
One-third of the study patients were randomized before 28 weeks’ gestation and the remaining two-thirds before 30 weeks. In addition, 57% of women were in their first pregnancy and slightly over half of patients had a cesarean delivery.
Median gestation was 28.9 weeks for the delayed clamping group and 29.2 weeks for the immediate clamping group.
Six women were excluded from results because they delivered after 35 weeks and one woman withdrew from the study.
Median time to clamping was 120 seconds and 11 seconds, respectively.
There was also immediate resuscitation, if needed, for both groups.
Delayed clamping resulted in a 5.2% infant death rate (7 of 135 infants), compared to 11.1% (15 of 135) for immediate clamping, for a risk difference of -5.9%.
For liveborn babies, median birth weight was 1108 g in the delayed clamping group and 1180 g in the immediate clamping group.
A lower median birth weight in the delayed clamping group implies that “net change in neonatal blood volume may not be relevant for very preterm births and supporting our hypothesis that continued umbilical flow has a role in the expanding pulmonary circulation during transition to the neonatal circulation,” the authors wrote.
For infants who survived, 32% (43 of 134) in the delayed clamping group had IVH versus 36% (47 of 132) in the immediate clamping group.
The study, which appears in the Fetal and Neonatal Edition of Archives of Disease in Childhood, builds on previous knowledge that if the umbilical cord is not clamped, umbilical flow continues longer than previously believed and that cord pulsation does not correlate with flow.
Also, a short delay in cord clamping may decrease risk of IVH and improve outcomes in preterm babies. However, previous small trials have excluded babies requiring resuscitation at birth.
The new study, which is the largest to date, shows that neonatal stabilization and resuscitation can be provided with the cord intact. But the authors said that a large multicenter trial is needed to assess the effect of resuscitating preterm babies with an intact cord.
To achieve the quality of neonatal care with the cord intact as demonstrated in the study, a multidisciplinary team approach was implemented, along with planning and training.
The study suggests performing neonatal care at the mother’s bedside is acceptable to women and their partners, including for resuscitation.
However, the authors argue against cord milking as an alternative intervention to cord clamping because it overrides the autoregulation of blood volume and blood pressure.
A strength of the study, besides being multicenter, is that it was conducted within existing clinical services. Independent adjudication of cranial ultrasound scans also improved the reliability in determining IVH.