Increased fetal brain perfusion and neonatal neurobehavioral performance in normally grown fetuses.

Objective: To explore the association between fetal cerebroplacental ratio (CPR) and frontal brain perfusion at third trimester with neonatal neurobehavioral performance in normally grown fetuses.

Methods: CPR and frontal brain perfusion measured by fractional moving blood volume (FMBV) were assessed in 258 consecutive healthy fetuses at routine third trimester scan (32-35.6 weeks). Neonates were evaluated with the Neonatal Behavioral Assessment Scale. The association between Doppler parameters and neurobehavior was analyzed by MANCOVA (multiple analysis of covariance) and logistic regression, with adjustment for smoking, socioeconomic class, mode of delivery, gestational age at birth, postnatal days at examination and gender.

Results: Fetuses with increased FMBV (in the upper quartile) had lower neurobehavioral scores in all areas, reaching significance in motor (5.6 vs. 5.8; p = 0.049), social (6 vs. 6.4; p = 0.006) and attention (5.3 vs. 5.9; p = 0.032). Fetuses with increased FMBV had higher risk of abnormal (<10th centile) motor (OR 3.3; 95% CI 1.36-8.1), social (OR 2.9; 95 CI% 1.33-6.5) and attention (OR 2.5; 95% CI 1.1-5.8) scores. Fetuses with lower CPR (in the lower quartile) did not differ in their neurobehavioral scores from those with normal values.

Conclusions: Normally grown fetuses with increased frontal brain perfusion have poorer neurobehavioral competences, suggesting a disrupted neurological maturation. The results support the existence of forms of placental insufficiency not detected by current definitions of growth restriction.