Auditory Neural Maturation After Exposure to Multiple Courses of Antenatal Betamethasone in Premature Infants as Evaluated by Auditory Brainstem Response

[摘要] OBJECTIVE. Our goal was to determine if multiple courses of antenatal betamethasone affect auditory neural maturation in 28 to 32 weeks' gestational age infants.PATIENTS AND METHODS. A retrospective cohort study was performed to compare auditory neural maturation between premature infants exposed to 1 course of betamethasone and infants exposed to ≥2 courses of betamethasone. Inclusion criteria included all 28 to 32 weeks' gestational age infants delivered between July 1996 and December 1998 who had auditory brainstem response testing performed (80-dB click stimuli at a repetition rate of 39.9/second) within 24 hours of postnatal life as part of bilirubin-auditory studies. Infants with toxoplasmosis, rubella, cytomegalovirus, herpes infections, chromosomal disorders, unstable conditions, exposure to antenatal dexamethasone, and exposure to <1 complete course of betamethasone were excluded. Auditory waveforms were categorized into response types on response replicability and peak identification as types 1 through 4 (type 1 indicating most mature). Absolute and interpeak wave latencies were measured when applicable. Categorical and continuous variables were analyzed by using the χ2 test and Student's t test, respectively.RESULTS. Of 174 infants studied, 123 received antenatal steroids. Of these, 50 received 1 course and 29 received ≥2 courses of betamethasone. There were no significant differences in perinatal demographics between the 2 groups. After controlling for confounding variables, there was no significant difference in mean absolute wave latencies, mean interpeak latencies, or distribution of response type between the 2 groups. There also was no significant difference in any auditory brainstem response parameters between infants exposed to 1 course of betamethasone ( n = 50) and infants exposed to >2 courses of betamethasone ( n = 17).CONCLUSION. Compared with a single recommended course of antenatal steroids, multiple courses of antenatal betamethasone are not associated with a deleterious effect on auditory neural maturation in 28 to 32 weeks' gestational age infants.

[学科分类] 儿科学