The Impact of Low Hematocrit at Birth on Very Low Birth Weight Infants

Background: Low hematocrit (HCT) at birth has been associated with intraventricular hemorrhage (IVH) in extremely premature infants. However, there is limited evidence of other neonatal outcomes in infants born with a low HCT. This study aims to evaluate the effects of low HCT at birth on neonatal outcomes in very low birth weight infants (VLBW).

Methods: Retrospective data of all VLBW infants born at LAC + USC Medical Center from 2009-2019 was gathered. Low HCT at birth was defined as a value of 40% or less. Short term neonatal outcomes and long term developmental outcomes were analyzed against low HCT.

Results: Of the 311 patients included in the study, 97 (31.2%) had low HCT at birth compared to 214 (68.8%) with normal HCT. Presence of a low HCT at birth was significantly associated with presence of acidemia in cord blood gas at delivery (24.2% vs 9.9% p = 0.001). Infants with low HCT were more likely to have a lower birth weight (1025 g vs 811g , p < 0.001) and gestational age (GA) (28.2 w vs 25.8 w, p < 0.001). These infants also had lower 5 minute Apgar scores (p < 0.001) and were significantly more likely to need intubation at birth (56% vs 43.4% p = 0.046), chest compressions in delivery room (23.1% vs 13.6% p = 0.045), and use of epinephrine in delivery room (7.9% vs 2.6% p = 0.038). Infants with low HCT levels were also significantly more likely to have intraventricular hemorrhage (IVH) (60.5% vs. 28.1% p < 0.001), severe IVH (11.2% vs 2.1% p = 0.001), bronchopulmonary dysplasia (BPD) (53.8% vs 24.6% p < 0.001), retinopathy of prematurity (ROP) (81.7% vs 43.1% p < 0.001), and severe ROP (22% vs 8.9% p = 0.004). Long term developmental outcomes were not significantly affected for infants born with low HCT. Logistic regression models identified increased IVH, BPD and ROP in infants with low HCT independent of GA (Table 1).

Conclusion: VLBW infants with low HCT at birth may require more extensive resuscitation at the time of delivery. These infants are at higher risk to develop IVH, BPD and ROP. Long term neurodevelopmental outcomes may not be significantly affected in infants born with low HCT.