Neonatal Hemoglobin Levels in Preterm Infants Are Associated with Early Neurological Functioning.

BACKGROUND

Neonatal anemia may compromise oxygen transport to the brain. The effects of anemia and cerebral oxygenation on neurological functioning in the early neonatal period are largely unknown.

OBJECTIVE

This study aimed to determine the association between initial hemoglobin levels (Hb) and early neurological functioning in preterm infants by assessing their general movements (GMs).

METHODS

A retrospective analysis of prospectively collected data on preterm infants born before 32 weeks of gestation was conducted. We excluded infants with intraventricular hemorrhage > grade II. On day 8, we assessed infants' GMs, both generally as normal/abnormal and in detail using the general movement optimality score (GMOS). We measured cerebral tissue oxygen saturation (rcSO2) on day 1 using near-infrared spectroscopy.

RESULTS

We included 65 infants (median gestational age 29.9 weeks [IQR 28.2-31.0]; median birth weight 1,180 g [IQR 930-1,400]). Median Hb on day 1 was 10.3 mmol/L (range 4.2-13.7). Lower Hb on day 1 was associated with a higher risk of abnormal GMs (OR = 2.3, 95% CI: 1.3-4.1) and poorer GMOSs (B = 0.9, 95% CI: 0.2-1.7). Hemoglobin strongly correlated with rcSO2 (rho = 0.62, p < 0.01). Infants with lower rcSO2 values tended to have a higher risk of abnormal GMs (p = 0.06). After adjusting for confounders, Hb on day 1 explained 44% of the variance of normal/abnormal GMs and rcSO2 explained 17%. Regarding the explained variance of the GMOS, this was 25% and 16%, respectively.

CONCLUSIONS

In preterm infants, low Hb on day 1 is associated with impaired neurological functioning on day 8, which is partly explained by low cerebral oxygenation.