The study found that cord milking provided greater benefits to preterm infants delivered by Cesarean section than current recommended practice.
A study of the impact of cord milking was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and published in Pediatrics.
Cord milking involves gently squeezing the umbilical cord with the thumb and forefingers, slowly massaging blood through the cord to the infant's abdomen after birth.
Previous research has suggested that delaying the clamping of the umbilical cord after birth for 30-60 seconds allows enough time for blood from the cord to fill the blood vessels in the newborn's lungs.
Experts believe that this delay helps reduce the risk of bleeding in the infant's brain cavities, known as intraventricular hemorrhage, thought to be caused by low blood pressure. This hemorrhaging can lead to several health problems for the baby, including delayed development, cerebral palsy and even death.
Dr. Anup C. Katheria, first author of the study and a neonatologist at the Neonatal Research Institute at the Sharp Mary Birch Hospital, became aware, however, that delayed cord clamping did not always reduce the risk of intraventricular hemorrhage in preterm infants delivered by Cesarean section.
Dr. Katheria and colleagues hypothesized that the anesthetic used in Cesarean delivery could impede the flow of blood through the umbilical cord. They decided to conduct a study to see if cord milking counteracts the reduced blood flow, providing the newborn with an improved supply of blood.
For the study, researchers from the Neonatal Research Institute at Sharp Mary Birch Hospital for Women and Newborns in San Diego, and Loma Linda University, CA, assessed 197 infants: 154 of whom were delivered by Cesarean and 43 delivered vaginally. The mothers of the infants went into labor before or during the 32nd week of pregnancy.
Cord milking improved blood circulation and hemoglobin levels
Infants delivered by Cesarean were randomly assigned to either a group whose umbilical cords were milked (75 infants) or a group who received delayed cord clamping (79 infants). The infants delivered vaginally were also randomly divided into two similar groups.
The researchers found that the infants delivered by Cesarean section who received cord milking had higher blood flow in the vein carrying blood from the brain to the heart and a higher output of blood from the right ventricle compared with those who received delayed cord clamping.
These measures indicate improved blood circulation in the brain and body. Those delivered by Cesarean section whose cords were milked were also found to have higher blood pressure and higher levels of hemoglobin in their blood.
No differences, however, were found by the researchers in the blood flow or blood pressure among the two groups of infants that were delivered vaginally.
In 2012, the American College of Obstetricians and Gynecologists recommended a 30-60-second delay before clamping the umbilical cord of all infants delivered preterm. The results of the new study suggest that among these infants, cord milking could provide greater benefits.
"The study results are very encouraging," says Dr. Tonse Raju, chief of the Pregnancy and Perinatology branch of the NICHD. "The findings need to be confirmed in a larger number of births, but at this point, it appears that umbilical cord milking may prove to be of great benefit to preterm infants delivered via Cesarean."
Previously, Medical News Today reported on a study suggesting that delaying umbilical cord clamping at birth could improve the child's long-term developmental prospects, leading to better social and motor skills for some children.