Comparison of Cerebral Hemodynamics among Hemodynamically Stable Preterm Small for Gestational Age and Appropriate...

Postnatal cerebral circulation and autoregulation are influenced by the degree of prematurity and fetal hypoxia. Currently, data on postnatal changes in cerebral blood flow indices in preterm and small for gestational age (SGA) neonates are limited. This study aimed to investigate the differences in cerebral hemodynamics between preterm (28^0/6-34^6/7 weeks), SGA, and appropriate for gestational age (AGA) neonates.

In this prospective cohort study conducted at a tertiary care center in South India in 2020-2021, cerebral hemodynamic parameters assessed by Doppler sonography findings in the first 72 hours of life were compared between hemodynamically stable SGA (n = 39) and AGA preterm neonates (n = 69) admitted to the neonatal intensive care unit.

Preterm SGA neonates demonstrated significantly lower pulsatility index (PI) and resistive index (RI) in the middle cerebral artery (MCA) on days 2 and 3. Linear mixed-effects analysis adjusted for gestational age, abnormal antenatal Doppler, multifetal gestation, antepartum hemorrhage, pregnancy-induced hypertension, preterm prelabor rupture of membranes, and mode of delivery showed significant differences in MCA RI between SGA and AGA preterm neonates. A significant group effect (p = 0.005) and group-time interaction (p = 0.009) were observed. The group effect for MCA PI remained statistically significant even after correction (adjusted p = 0.018), while all other Doppler variable associations lost statistical significance.

Low PI and RI in the MCA suggest altered cerebral hemodynamics in preterm SGA neonates with lower vascular impedance and cerebral vasodilation compared with AGA neonates.

· Studies on postnatal changes in cerebral blood flow in SGA neonates are limited.. · SGA preterm infants have lower MCA RI and PI, indicating lower vascular impedance.. · Further studies are needed to understand the long-term impact..