According to researchers, there's a technique for increasing blood flow into a baby's umbilical cord, boosting blood pressure and the amount of red blood cells for a preterm infant delivered via cesarean section.

In a study published in the journal Pediatrics, researchers elaborated on how "umbilical cord milking" can be utilized to improve circulatory function in infants over the usual practice of waiting up to 60 seconds before clamping and cutting the umbilical cord. Cord milking consists of gently squeezing the umbilical cord and encircling it around the fingers to slowly push blood through the cord and into the abdomen of an infant.

Cord milking benefits – like improved blood flow to and from the heart, higher blood pressure and red blood cell count – were, however, only observed in infants delivered via cesarean section. Infants born through vaginal births did not register differences in blood volume or pressure whether they underwent cord milking or delayed cord clamping.

For the study, researchers worked with 197 infants from mothers who went into labor before or at their 32nd week of pregnancy. Of these, 154 were delivered via cesarean section, 75 of whom were randomly assigned to undergo cord milking while 79 were administered delayed clamping. There were 43 infants in the vaginal birth group.

Those in the cord milking group specifically showed higher blood flow in the superior vena cava – the large vein responsible for directing blood from the brain back to the heart – and a higher blood output from the right ventricle.

Why does cord milking work?

Researchers reasoned that the massaging effect of the technique improved blood flow in the umbilical cord, which increased the amount of blood supplied to the infant. There is possibly a reduction in blood flow through the umbilical cord due to anesthesia used for cesarean delivery. The anesthetic reduces contractions in the uterus — which also reduces the force that pushes blood through the umbilical cord.

Cord milking and delayed clamping are both techniques aimed at improving blood flow through the umbilical cord, protecting an infant from intraventricular hemorrhage or bleeding in brain cavities called ventricles. The condition is believed to be a result of low blood pressure caused by having too little blood circulating in the body. Brain bleeds in babies can cause cerebral palsy, developmental delays and, in extreme cases, death.

Researchers from the Loma Linda University and Sharp Mary Birch Hospital for Women and Newborns' Neonatal Research Institute contributed to the study, with support from the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

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