However, the researchers, led by Anup Katheria, MD, director, Neonatal Research Institute Team, Sharp Mary Birch Hospital for Women and Newborns, San Diego, and assistant clinical professor, Loma Linda University, California, found no similar trend in the smaller number of preterm infants delivered vaginally.
The study included 197 infants born with a mean gestational age of 28 weeks. Forty-three infants were delivered vaginally, with 23 randomly assigned to UCM and 20 to delayed clipping. Another 154 were delivered by cesarean, with 75 randomly assigned to UCM and 79 to delayed clamping for at least 45 seconds. The infants underwent echocardiogram at between 6 to 12 hours of life, and continuous hemodynamic recordings were made at one of the two study centers for 140 subjects: 70 in each group. The clinicians were blinded with respect to the infants' study group.
The investigators found higher superior vena cava blood flow and higher right ventricular output in the first 12 hours of life among cesarean-delivered infants in the UCM group, which was the primary endpoint of the trial, compared with infants who had delayed clamping. Hemodynamic testing also documented improved hemoglobin, higher delivery room temperature, and higher blood pressure in the first 15 hours of life, as well as higher urine output in the first 24 hours among cesarean-delivered infants in the UCM group.
Because the incidence of intraventricular hemorrhage (IVH) was lower than anticipated, attempts to determine whether UCM affected IVH incidence were discontinued. The authors estimate the trial would have required 780 infants in each group and 7 years to complete to gain statistically valid data on IVH.
The study is the largest to compare UCM with delayed cord clipping in cesarean-delivered infants, the authors write. It was the first to demonstrate improvements in placental transfusion, as seen by higher hemoglobin, improved hemodynamics, and improved urine output.
In 2012, the American College of Obstetricians and Gynecologists began recommending a 30- to 60-second delay in umbilical cord clamping in all preterm deliveries, which has led to decreased incidence in IVH. However, the statement acknowledged limited data on the ability of delayed cord clamping's ability to improve placental transfusion during cesarean delivery (CD).
UCM should no longer be considered experimental, the authors write, noting it has been studied in seven randomized controlled trials and nine controlled trials over the course of the last 60 years in both term and preterm infants, documenting its safety and efficacy.
"UCM provides a greater placental transfusion, as demonstrated by higher initial [hemoglobin], higher blood pressure, and improved [systemic blood flow] and urine output for infants delivered by CD. UCM may be preferable in preterm infants delivered by CD, particularly in newborns when immediate resuscitation is needed," the authors write. "Although more larger trials are needed to confirm our observations, UCM should be considered as a beneficial option for preterm infants delivered by CD."
All phases of the study were supported by a National Institutes of Health grant. The authors have disclosed no relevant financial relationships.
Pediatrics. 2015;136:61-69. Abstract
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