Delaying umbilical cord clamping for preterm infants results in better motor development

The results of the six-year study of infants born before 32 weeks of age, conducted by URI Nursing Professor Emeritus Judith S. Mercer and URI Associate Professor of Nursing Debra A. Erickson-Owens at Women & Infants Hospital, a Care New England Hospital, were released today in The Journal of Pediatrics.

The research project, which ran from 2008 to 2014, was funded by a $2 million National Institute for Nursing Research grant and more than $300,000 from the Thrasher Research Fund, which were awarded to Mercer, the principal investigator, and Erickson-Owens, co-principal investigator. This was the first randomized study of its kind of very low birth weight infants examining the long-term impact of delayed cord clamping and cord milking.

Delayed clamping and milking support the return of the infant's blood from the placenta and increases iron-rich red blood cells, stem cells and blood volume.

At 18 months of age, there were 161 infants examined and only nine (13 percent) of the babies who had delayed cord clamping scored lower than 85 on the Bayley III Motor Composite, compared to 23 (28 percent) of those whose cords were clamped immediately. The Bayley III motor assessment can measure a baby's gross and fine motor function from 1 to 42 months. Scoring an 85 or above (100 is average) is considered a normal range while less than 85 can be concerning. In Mercer and Erickson-Owens's study, more infants with immediate clamping scored below the normal range.

"Motor development is so critical for babies because it is how they learn, how they experience the world," Mercer said. "When you see a baby, he or she is always reaching out, touching, grasping things and even putting things in their mouths."

"If the child had delayed cord clamping, the child's chance of scoring less than 85 on the Bayley-III motor composite score was reduced by 68 percent after adjusting for known risk factors," according to the article in The Journal of Pediatrics.

"If you can wait 45 seconds before clamping the cord, and that delay has a chance of improving your baby's motor function, wouldn't you make that choice to delay?" Erickson-Owens said. "It makes us consider what other positive things occur with delaying that could result in a long-term impact on infant well-being.

"When you have a two-times chance of scoring lower than an 85 with immediate cord clamping, what is evidence-based practice telling a practitioner to do? Everyone is looking for ways to reduce morbidity and mortality in preterm infants, and this could be one step," Erickson-Owens said.

Joining the two certified nurse-midwives on the research team were Betty R. Vohr, physician and director of Women & Infants Hospital's Neonatal Follow-up Clinic; Richard J. Tucker, senior research data analyst and statistician; Ashley B. Parker, research assistant; William Oh, physician and former principal investigator of the Women & Infants/Brown Center of the Neonatal Research Network of the National Institute of Child Health and Human Development; and James F. Padbury, pediatrician-in-chief and chief of Neonatal/Perinatal Medicine at Women and Infants Hospital.

"This research, led by Judith Mercer, demonstrates that a clinical maneuver as simple as delayed umbilical cord clamping can have a profound effect on early neonatal and importantly later newborn developmental outcomes," Padbury said. "We are pleased to see how widely adopted this practice is becoming."

This research follows a preliminary study of 72 very low birth weight infants completed in 2006, which showed that delayed cord clamping protected them from bleeding in the brain (intraventricular hemorrhage) and infection (late onset sepsis). Mercer and Erickson-Owens examined those factors in the recent, more expanded study. But the new findings did not support their hypothesis that infants with delayed clamping would have less intraventricular hemorrhage and less infection. The two researchers said the data showed that confounding factors present prior to birth, such as infection and high blood pressure in the mother had a powerful effect on the preterm infants. The mothers in this study had a preponderance of infection and high blood pressure, Erickson-Owens said.

The researchers also said one of the study's major limitations was the lack of a normal preterm control group. "By their very nature, preterm births are not normal" Mercer said. "But, even this brief conservative cord clamping protocol appears to benefit the very preterm infants at 18 to 22 months of corrected age," the researchers said in their study.

That's why an ongoing $2.4 million National Institutes of Health study led by Mercer and Erickson-Owens comparing the effects of delayed clamping and cord milking versus immediate cord clamping on full-term babies is critical to the discussion. The study, which also involves Women & Infants Hospital and Brown University, received an additional $100,000 in support from the Bill & Melinda Gates Foundation.

Mercer and Erickson-Owens's team is studying babies from birth to 24 months of age to measure the effects of delaying cord clamping and milking on the structure and functioning of the developing brain in full-term infants. The researchers are studying infants born at Women & Infants. They are working with the Advanced Baby Imaging Laboratory at Brown University using magnetic resonance imaging (MRI) technology at 4, 12 and 24 months to look at the effects of the additional iron (from red blood cells) the infant receives with delayed cord clamping on brain myelin development and behavior.

Myelin sheaths are insulating coverings that enhance the speed at which nerve impulses travel.