Impact of Delayed Cord Clamping on Red Blood Cell Transfusion in Very Low Birthweight Infants

Background: Very low birthweight (VLBW) preterm infants (under 1500g) receive multiple red blood cell (RBC) transfusions. RBC transfusions are associated with significant morbidities that include necrotizing enterocolitis and retinopathy of prematurity. Transfusion prevention strategies including RBC transfusion guidelines and delayed cord clamping (DCC) were implemented in the University of Maryland Neonatal Intensive Care Unit and labor and delivery unit in 2017 and 2018, respectively. We hypothesized that DCC, which facilitates placental transfusion, will decrease the RBC transfusion requirements in VLBW infants. The objective of this study was to determine 1) the annual RBC transfusion burden in the NICU over 5 years and 2) the effect of DCC on the number and rate of RBC transfusions in VLBW infants.

Methods: Following IRB approval, a retrospective medical chart review was performed in 787 VLBW infants ≥22wks gestational age that were admitted to the UMD NICU between 2016 and 2020. Demographic factors (birthweight (BW), gestational age (GA), and race), number of RBC transfusions, and DCC status were collected to determine associations between DCC and RBC transfusion. Data analysis included Chi-square tests and linear regression methods.

Results: The median BW was 1000g (260-1500) and mean GA was 28wks (22-37). There was not a significantly yearly trend for transfusion status in VLBW infants, but there was a decreasing annual trend in 2019 and 2020 in the number of RBC transfusions in the VLBW 1000-1250g and 1250-1500g population compared to the extremely low birthweight (ELBW) ( <1000g) population. Infants under 1000g (174) and infants <29wks (208) received significantly more transfusions compared to VLBW infants 1000-1250g (56), 1250-1500g (106) and >29wks (151) (Table, p<0.05). Of the 538 subjects that met inclusion criteria, 81 babies received DCC (15%), with larger GA infants being more likely to receive DCC than smaller GA infants. There was a strong correlation between DCC and negative transfusion status (Table, p<0.01) after adjusting for BW and GA. Preterm infants that received DCC were 55% less likely to receive transfusions compared to babies that did not receive DCC. Furthermore, at any given GA, the number of transfusions that infants received was 25% lower in infants that received DCC (p < 0.05) (Figure).

Conclusion: A decrease in transfusions in 2019-2020 in the 1000-1250g and 1250-1500g populations coincided with the increasing compliance to the practice of DCC. Despite a smaller proportion of infants receiving DCC, placental transfusion significantly reduced the number of transfusions in VLBW infants. Nonetheless, DCC is difficult to implement consistently in this smaller and vulnerable ELBW preterm population due to the need for timely neonatal resuscitation and prevention of hypothermia. Until the practice of DCC is able to be safely implemented without jeopardizing timely resuscitation in ELBW infants, one must continue to focus on minimizing phlebotomy loss and conserving blood.