Abnormal antenatal Doppler velocimetry and cognitive outcome in very-low-birth-weight infants at 2 years of age

OBJECTIVE

To study neurodevelopmental outcome at 2 years of corrected age in very-low-birth-weight (VLBW) (< or = 1500 g) preterm infants with abnormal fetoplacental flow.

METHODS

A total of 258 VLBW infants were born at Turku University Hospital between 2001 and 2006. Of these, 99 had undergone, within 1 week of delivery, antenatal Doppler assessment of blood flow in the umbilical artery (UA), fetal middle cerebral artery (MCA), descending aorta (DAo), aortic isthmus and ductus venosus and were eligible for inclusion in the study. Postnatally brain pathology was assessed by serial ultrasound and magnetic resonance imaging in 86 of the neonates and brain volume was measured in 80. Cognitive development was evaluated at 2 years of corrected age in 83 infants using the Bayley Scales of Infant Development-II. Motor development was assessed using the Hammersmith Infant Neurological Examination.

RESULTS

On univariate analysis, abnormal pulsatility index (PI) in the UA and an abnormal UA-PI/MCA-PI ratio (P = 0.04 and P = 0.003, respectively) as well as increases in both the DAo-PI and in the DAo-PI/MCA-PI ratio (P = 0.03 and P = 0.02, respectively), were associated with adverse cognitive outcome at 2 years of age. However, when controlling for cerebral volume using multivariate analysis, the association between abnormal antenatal Doppler characteristics and cognitive outcome became statistically non-significant, which indicated the determinant role of the volume reduction. Motor development was not associated with antenatal Doppler indices.

CONCLUSION

Abnormal antenatal Doppler indices are associated with adverse cognitive outcome at 2 years in VLBW infants. Our findings suggest that this association may be mediated through brain volume.

Cognitive outcome at 2 years of age in Finnish infants with very low birth weight born between 2001 and 2006

AIM

To study cognitive outcome of premature, very low birth weight (VLBW) infants in relation to parental education and neonatal data.

METHODS

A regional cohort of 182 VLBW infants born between 2001 and 2006 was followed up. Brain ultrasounds (US) were examined serially until term age and brain magnetic resonance imaging at term age. Neurological status was examined systematically. Cognitive development was assessed using the Mental Developmental Index (MDI) of Bayley Scales at 2 years of corrected age. A total of 192 healthy full-term (FT) controls were assessed with the MDI at 2 years of age.

RESULTS

The mean MDI in VLBW infants was 101.7 (SD 15.4), which was lower compared with FT controls (109.8, SD 11.7, p < 0.001). In regression analysis of the demographic and medical data of VLBW infants, postnatal corticosteroids (p = 0.04), intestinal perforation (p = 0.03) and major brain pathology (p = 0.02) were negatively associated with the MDI. In VLBW infants, the prevalence of neurodevelopmental impairment was 9.9% (3.3% MDI below 70, 7.1% cerebral palsy, 2.2% hearing aid, no blind infants).

CONCLUSION

Cognitive development of VLBW infants seemed to have improved in comparison with earlier publications, but it differed from the FT controls. Neonatal factors affected cognitive development. Therefore, updated regional follow-up data are important for clinicians.