Accelerated postnatal head growth follows preterm birth

Abstract

Background: Poor growth after preterm birth, particularly poor head growth, is associated with impaired neurodevelopmental outcome.

Objective: To evaluate weight gain and head growth between birth and term in a contemporary cohort of preterm infants, taking into account breast milk intake and illness severity.

Methods: Subjects were inborn infants ≤32 weeks gestation who remained in the neonatal unit up to ≥37 weeks postmenstrual age. Weight and head circumference (HC) were expressed as standard deviation score (SDS), growth between birth and discharge as SDS gain (SDSG), and illness severity and breast milk exposure as the number of days of level 1 (full) intensive care (%L1IC) and the number of days on which breast milk was received (%BM) as a percentage of days from birth to discharge.

Results: Infants showed poor postnatal weight gain but accelerated head growth. There was a highly significant fall in mean (SD) weight SDS between birth and discharge (−0.31 (0.96) and −1.32 (1.02) respectively, p<0.001) and a highly significant increase in HC SDS (−0.52 (0.95) and −0.03 (1.25) respectively, p  =  0.003). %L1IC had a highly significant negative impact on weight SDSG (p  =  0.006), and %BM had a significant positive impact on HC SDSG (p  =  0.043).

Conclusions: Accelerated postnatal head growth suggests catch up after antenatal restraint. This raises the possibility that poor neurocognitive outcomes after extremely preterm birth may in part be consequent on poor intrauterine brain growth. As postnatal head growth may be facilitated by breast milk, there is an urgent need to evaluate the optimal use of breast milk in preterm neonates. Illness severity is a significant determinant of poor postnatal weight gain.