Abstract 1383 Neurodevelopmental Disabilities Poster Symposium, Tuesday, 5/4

Background: Previous studies have suggested accelerated maturation in preterm (PT) infants with Intrauterine Growth Restriction (IUGR).

Method: We measured rate of neuromotor maturation with serial Neonatal Neurodevelopmental Examinations in preterm (PT) IUGR infants with birthweight (BW) <1500 gms and ≤10% for gestational age (GA). We compared 42 IUGR infants to 54 low risk appropriate for gestational age (AGA) preterm infants with BW <1500 gms. Rate of neuromotor maturation in these infants is described by plotting Maturity Score from each Neurodevelopmental Exam (the sum of measures of tone, reflexes and responses) against Postmenstrual Age (PMA), drawing a line of best fit using SPSS, and determining the slope and a y-intercept (Maturity Score at 32 wks PMA) for each infant. These PT infants were born at or transferred within 1 wk to JHH, 6/94-7/98, and examined weekly with ≥2 Neurodevelopmental Examinations.

Results: IUGR infants had higher GA than PT AGA controls. Maturity Score @ 32 wks PMA was lower in IUGR infants than PT AGA controls, as were Reflex Subscore @ 32 wks PMA and Tone Slope. Using linear regression, only IUGR and GA were significantly related to Maturity Score @ 32 wks PMA (congenital anomalies, abnormal cranial ultrasound and chronic lung disease were not related). When we excluded the 13 (35%) IUGR infants with any congenital anomaly and again compared IUGR with AGA infants, only Reflex Subscores @ 32 wks PMA were significantly lower in IUGR infants. *p<0.05 **p<0.01 (Table)

Table 1 No caption available
Full size table

Conclusion: These extremely preterm IUGR infants had delayed neuromotor maturation prior to term. In contrast, IUGR infants born closer to term have accelerated maturation, presumably a benefit of compensatory intrauterine mechanisms that stimulate maturation. Our smaller, more immature infants are more severely growth restricted by virtue of their age of presentation. We speculate that delayed maturation in these extremely preterm IUGR infants is due to decompensation in utero and/or unsuspected CNS abnormalities.