Association between fetal growth, cerebral blood flow and neurodevelopmental outcome in univentricular fetuses

Abstract

Objective To investigate the association of fetal growth and cerebrovascular resistance at different periods in gestation with neurodevelopment (ND) at 14 months in the univentricular subject. Methods We reviewed serial prenatal ultrasound (US) examinations from 133 infants enrolled in the Pediatric Heart Network's Single Ventricle Reconstruction or Infants with Single Ventricle trials, including a subset of 82 infants in whom ND was assessed at 14 months using mental (MDI) and psychomotor (PDI) developmental indices. US examinations were assigned to one of four gestational time periods: (1) 20-23 weeks, (2) 24-29 weeks, (3) 30-33 weeks and (4) ≥ 34 weeks. Middle cerebral artery (MCA) flow velocity was measured and pulsatility index (PI), a measure of downstream resistance, was calculated. Data on fetal head circumference (HC), femur length, abdominal circumference (AC) and estimated fetal weight (EFW) were collected and their Z-scores were calculated. We evaluated the rate of change of these parameters over time within individuals, tested correlations between fetal growth and ND and assessed predictors of ND using linear regression. Results The mean prenatal HC Z-score was < 0 at each gestational-age period and became more negative later in pregnancy. There was less growth in HC from time period 3 to period 4 compared with from period 2 to 3 (Δ HC Z-score, -0.07 ± 0.1 vs 0.11 ± 0.22, P = 0.03). Though ND did not correlate with HC, HC Z-score or MCA-PI Z-score, HC growth from period 2 to period 3 correlated with MDI (r = 0.45, P = 0.047). AC Z-score in period 4 predicted MDI (β = 4.02, P = 0.04). EFW Z-score and AC Z-score in period 2 predicted PDI (β = 10.6, P = 0.04 and β = 3.29, P = 0.047, respectively). Lower MCA-PI at initial US predicted higher PDI (β = -14.7, P = 0.03). Conclusion In univentricular fetuses, lower cerebrovascular resistance may be protective for ND. Decreased fetal somatic growth may predict developmental abnormalities.