Umbilical cord milking may be linked to higher risk of brain bleeding in preterm infants

November 19, 2019

Milking the umbilical cord--gently squeezing the cord and pushing the contents into the newborn's abdomen before clamping the cord--could increase the risk for severe intraventricular hemorrhage, or bleeding into the brain's fluid-filled cavities, in extremely preterm infants, according to results of a study funded by the National Institutes of Health that was halted for safety concerns.

The study, led by Anup Katheria, M.D., of the Sharp Mary Birch Hospital for Women and Newborns in San Diego and colleagues at institutions in the United States and Europe, had sought to determine if cord milking was an alternative to delayed cord clamping. Unlike cord milking, a delay in clamping allows time for the blood to flow naturally from the cord into the abdomen before clamping and cutting the cord.

After extremely preterm infants (23 to 27 weeks gestation) in the cord milking group were found to have more hemorrhages inside the ventricles, compared to the earliest preterm infants in the delayed clamping group, the study was stopped before enough infants could be enrolled to allow for a statistically valid analysis.

Some studies of term infants have found that delayed cord clamping reduces the chances of anemia and appears to benefit cognitive development in early childhood. In preterm infants, however, the extra time needed for delayed cord clamping also may delay the start of the respiratory support often needed for the infants' underdeveloped lungs.

"Although it's not possible to draw definitive conclusions, the results suggest extreme caution in performing cord milking in this vulnerable group of infants," said Caroline Signore, M.D., of NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development, who oversaw the study.

An earlier study comparing umbilical cord milking to delayed cord clamping in preterm infants delivered by cesarean suggested that cord milking resulted in higher blood flow and benefits in cognitive development by 2 years of age. A meta-analysis of studies dating back to the 1940s found that preterm infants who underwent cord milking had evidence of higher blood volume, lower risk of bleeding into the ventricles, and a lower likelihood of requiring oxygen therapy. The authors were unaware of any previous studies demonstrating harm from umbilical cord milking.

In the current study, appearing in the Journal of the American Medical Association, the researchers enrolled women at less than 32 weeks of pregnancy at risk for preterm birth. When the women went into early labor, their infants were assigned at random to umbilical cord milking or delayed cord clamping for 60 seconds. For safety reasons, obstetricians could opt out of either procedure and immediately clamp the cord.

Researchers planned to enroll 1,500 infants, with 750 assigned at random to each group. Before the study was halted, 474 infants were randomized, with 236 assigned to cord milking and 238 assigned to delayed clamping.

The study authors classified the results into a single combined outcome: death or severe intraventricular hemorrhage. Among the cord milking group, 29 infants (12%) died or developed severe intraventricular hemorrhaging, compared to 20 infants (8%) in the delayed clamping group, a difference that was not statistically significant.

When the authors considered only the death rate, it also did not differ significantly between the two groups: 7% in the cord milking group vs. 8% in the delayed clamping group.

However, the rate of severe intraventricular hemorrhage was significantly higher in the cord milking group: 8% (20 infants), compared to 3% (8 infants) in the delayed clamping group. Among those in the cord milking group, all 20 with intraventricular hemorrhage were the youngest preterm infants, born in weeks 23 to 27 of pregnancy, compared to 5 of the 8 infants in the delayed clamping group. Among infants born at 28 to 32 weeks, no intraventricular hemorrhage occurred in the cord milking group, and three cases occurred in the delayed clamping group, a rate that did not differ significantly.

Compared to more mature preterm infants, extremely preterm infants' circulatory systems have difficulty regulating blood flow in the brain. The authors theorize that the increase in blood flow resulting from cord milking could have stressed the blood vessels in their brains, making them more likely to rupture. The authors noted that previous studies have shown a higher rate of severe intraventricular hemorrhage in preterm infants delivered vaginally, compared to those delivered by cesarean.

Because the higher risk of intraventricular hemorrhage was found only in extremely preterm infants, the authors are continuing to compare cord milking to delayed clamping in preterm infants born at 30 to 32 weeks and will evaluate development of the two groups at 2 years of age.
-end-
Reference

Katheria, A, et al Association of umbilical cord milking vs delayed umbilical cord clamping with death or severe intraventricular hemorrhage among preterm infants. Journal of the American Medical Association. 2019.

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD leads research and training to understand human development, improve reproductive health, enhance the lives of children and adolescents, and optimize abilities for all. For more information, visit http://www.nichd.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

NIH/Eunice Kennedy Shriver National Institute of Child Health and Human Development

Related Infants Articles from Brightsurf:

Most infants are well even when moms are infected by COVID-19
Infants born to women with COVID-19 showed few adverse outcomes, according to the first report in the country of infant outcomes through eight weeks of age.

Probiotic may help treat colic in infants
Probiotics -- or 'good bacteria' -- have been used to treat infant colic with varying success.

Deaf infants' gaze behavior more advanced than that of hearing infants
Deaf infants who have been exposed to American Sign Language are better at following an adult's gaze than their hearing peers, supporting the idea that social-cognitive development is sensitive to different kinds of life experiences.

Initiating breastfeeding in vulnerable infants
The benefits of breastfeeding for both mother and child are well-recognized, including for late preterm infants (LPI).

Young infants with fever may be more likely to develop infections
Infants with a high fever may be at increased risk for infections, according to research from Penn State College of Medicine.

Early term infants less likely to breastfeed
A new, prospective study provides evidence that 'early term' infants (those born at 37-38 weeks) are less likely than full-term infants to be breastfeed within the first hour and at one month after birth.

Infants are more likely to learn when with a peer
Researchers at the University of Connecticut and University of Washington looked at the mechanisms involved in language learning among nine-month-olds, the youngest population known to be studied in relation to on-screen learning.

Allergic reactions to foods are milder in infants
Majority of infants with food-induced anaphylaxis present with hives and vomiting, suggesting there is less concern for life-threatening response to early food introduction.

Non-dairy drinks can be dangerous for infants
A brief report published in Acta Paediatrica points to the dangers of replacing breast milk or infant formula with a non-dairy drink before one year of age.

Infants can't talk, but they know how to reason
A new study reveals that preverbal infants are able to make rational deductions, showing surprise when an outcome does not occur as expected.

Read More: Infants News and Infants Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.