Neurodevelopmental outcome of full-term small-for-gestational-age infants with normal placental function

To evaluate the 2-year neurodevelopmental outcome of full-term, small-for-gestational-age (SGA) newborns with normal placental function, according to current criteria based on umbilical artery Doppler findings.

A cohort of consecutive full-term, SGA newborns with normal prenatal umbilical artery Doppler was compared with a group of full-term, appropriate-for-gestational-age (AGA) infants sampled from our general neonatal population. Neurodevelopmental outcome was evaluated at 24 months' corrected age using the Bayley Scales of Infant and Toddler Development, 3(rd) Edition (Bayley-III), which evaluates cognitive, language, motor, social-emotional and adaptive competencies. The effect of the study group on each domain was adjusted with MANCOVA and logistic regression for gestational age at delivery, socioeconomic status, gender, tobacco smoking and breastfeeding.

A total of 223 infants (112 SGA and 111 AGA) were included. The groups differed significantly with respect to socioeconomic status and gestational age at delivery. All studied neurodevelopmental domains were poorer in the SGA group, reaching significance for the cognitive (92.9 vs 100.2, adjusted P = 0.027), language (94.7 vs 101, adjusted P = 0.025), motor (94.2 vs 100, adjusted P = 0.027) and adaptive (89.2 vs 96.5, adjusted P = 0.012) scores. Likewise, the SGA group had a higher risk of low scores in language (odds ratio (OR) = 2.63; adjusted P = 0.045) and adaptive (OR = 2.72; adjusted P = 0.009) domains.

Compared with normal-sized babies, full-term SGA infants, without placental insufficiency defined according to currently used criteria, have lower 2-year neurodevelopmental scores. These data challenge the concept that SGA fetuses with normal umbilical artery Doppler are 'constitutionally small' but otherwise completely normal.