Brainstem maturation after antenatal steroids exposure in premature infants as evaluated by auditory brainstem-evoked response.
OBJECTIVE
Antenatal steroids result in fetal lung maturation, but may retard brain development. Auditory brainstem-evoked response (ABR) is a noninvasive assessment of brainstem maturation. The objective of this study was to determine if antenatal steroids affect brainstem maturation in infants </=32 weeks gestational age (GA).


METHODS
Bilateral monaural ABR were performed within the first 24 hours using 80 db nHL unfiltered click stimuli at a repetition rate of 39.9/seconds. ABR waveforms were categorized into Response Types based on response replicability and peak identification. Absolute wave latencies and interpeak latencies were measured when applicable. Data were collected for antenatal steroid exposure, mode of delivery, chorioamnionitis in utero, exposure to illicit drugs, exposure to magnesium sulfate, mechanical ventilation and 5 minute Apgar score <5 minute. Infants with TORCH infections, unstable conditions, and chromosomal disorders were excluded.


RESULTS
Of 186 infants studied, 130 received antenatal steroids. Data were analyzed in 2 week GA intervals. There was a significant difference (P<0.05) in race (29 vs 39% African-American), birth weight (1231 vs 1416 gm) and use of magnesium sulfate (60 vs 32%) among infants who did and did not receive antenatal steroids, respectively. There was no significant difference in the other parameters measured. Even after controlling for confounding variables, there was no difference between absolute wave latencies or interpeak latencies between groups at either 28 to 29 weeks' or 30 to 31 weeks' postmenstrual age. There was no significant difference in frequency distribution of ABR waveform Response Types between groups.


CONCLUSIONS
Antenatal steroids have neither a deleterious nor beneficial effect on brainstem maturation as measured by ABR in infants at </=32 weeks GA.
Amin
Sanjiv B
SB
Department of Pediatrics, Division of Neonatology, Strong Children's Hospital, USA.
Orlando
Mark S
MS
Dalzell
Larry E
LE
Merle
Kathleen S
KS
Guillet
Ronnie
R
D001623:Betamethasone / Q000494:pharmacology*; D001933:Brain Stem / Q000187:drug effects* / Q000196:embryology* / Q000503:physiopathology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D005325:Fetal Organ Maturity / Q000187:drug effects / Q000502:physiology; D005865:Gestational Age; D005938:Glucocorticoids / Q000494:pharmacology*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008168:Lung / Q000187:drug effects* / Q000196:embryology* / Q000503:physiopathology; D008297:Male; D011247:Pregnancy; D011295:Prenatal Care; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
D005938:Glucocorticoids; D001623:Betamethasone