Association of antenatal and postnatal dexamethasone exposure with outcomes in extremely low birth weight neonates.

Background: Recent studies of preterm neonates have indicated that antenatal dexamethasone (ADX) may have adverse effects on cranial ultrasound findings at the time of hospital discharge, including periventricular leukomalacia. Furthermore, both ADX and postnatal dexamethasone (PDX) may have adverse effects on subsequent neurodevelopmental outcome.

Objectives: 1) To assess the effects of ADX exposure on cranial ultrasound findings at the time of hospital discharge and 2) to evaluate the individual effects of ADX and/or PDX exposure on subsequent neurodevelopmental outcome in extremely low birth weight (ELBW) neonates in whom confounding risk factors known to influence outcome were controlled.

Methods: One hundred seventy-three ELBW (< or =1000 g) neonates were studied using a prospectively collected database and hospital and clinic records. Study patients were assigned to 1 of 4 groups according to dexamethasone exposure: group I, no dexamethasone exposure; group II, ADX exposure to hasten fetal lung maturity; group III, PDX exposure for chronic lung disease; group IV, both ADX and PDX exposure. The 4 groups were compared using multinomial logistic regression or analysis of covariance to control for confounding variables. Primary outcome variables were cranial ultrasound findings at hospital discharge and results of developmental testing at 18 to 22 months' corrected age (Bayley Scales of Infant Development).

Results: Cranial ultrasound results as well as Bayley Scales of Infant Development scores were similar in groups I and II and in groups III and IV. The likelihood of abnormal cranial ultrasound studies and lower scores on neurodevelopmental testing was greater in groups III and IV versus groups I and II. In this study, ADX did not seem to increase the risk of periventricular leukomalacia.

Conclusions: ADX exposure is not associated with an increase in abnormal cranial ultrasound findings in ELBW neonates. PDX exposure, but not ADX exposure, is associated with worse neurodevelopmental outcome in this population. These results are supportive of the recent statement by the American Academy of Pediatrics (Committee on Fetus and Newborn) and the Canadian Paediatric Society (Fetus and Newborn Committee) and emphasize that PDX should be used with caution in ELBW neonates.