A National Institutes of Health-funded study suggests that providing a higher threshold of red cells within clinically accepted limits offers no advantage in survival or reduction in neurological impairment over a lower threshold.

The study, which appears in The New England Journal of Medicine, is the largest to-date to compare thresholds for blood transfusions in premature babies, according to the press release.

Very preterm infants, or those born before 29 weeks of pregnancy, and those weighing less than 1000 grams are at high risk for anemia because of their early stage of development, reduced ability to produce red blood cells, and need for blood sampling as part of their intensive medical care.

Previous studies suggest that anemic infants who received transfusions at a higher hemoglobin threshold within the currently accepted range would have a lower risk of death or developmental problems. Measuring hemoglobin, a protein produced in red blood cells, indicates the proportion of red blood cells, according to the press release. Therefore, hemoglobin transfusions thresholds for preterm infants vary according to weight, stage of maturity, and other factors, the study authors noted.

Of the 895 infants assigned to a higher hemoglobin threshold, 50.1% died or survived with a neurodevelopmental impairment, compared with 49.8% of 897 infants assigned to a lower threshold. When the 2 component outcomes were evaluated separately, the 2 groups also had similar rates of death and of neurodevelopment impairment.

Further, the study authors evaluated the babies at 2 years of age and concluded that a higher hemoglobin threshold increased the number of transfusions but did not improve the chance of survival without neurodevelopmental impairment.

"The findings are likely to be used to guide transfusion practice in the future for these infants; studies in premature infants are needed to guide care for these small and vulnerable infants; studies funded by NIH in multi-site networks are vitally important to the health of these fragile babies,” said Rosemary Higgins, MD, of George Mason University’s College of Health and Human Services, in a press release.

Transfusions with higher red blood cell levels do not improve preterm baby outcomes. EurekAlert! https://www.eurekalert.org/pub_releases/2020-12/gmu-twh123020.php. Published December 31, 2020. Accessed January 5, 2021.