Impact of Gestational Age on Neonatal Hearing Screening in Vaginally-Born Late-Preterm and Early-Term Infants

<b><i>Background:</i></b> Late-preterm and early-term (LP-ET) infants, defined herein as 35&#8304;-37⁶ weeks' gestation, often fail on 1st otoacoustic emissions (OAE) test. Hypothesis: LP-ET infants fail more than term infants (38&#8304;-42 weeks' gestation) on the 1st OAE test. <b><i>Aim</i></b>: To evaluate the effect of gestational age on the 1st OAE test. <b><i>Methods:</i></b> We studied 1,572 vaginally-delivered (VD) infants ≥35 weeks' gestation (1.1.2011-30.9.2011). Perinatal and neonatal variables and results of OAE tests were recorded. <b><i>Results:</i></b> LP-ET infants, compared to full-term infants, had a significantly 2-fold higher need for repeated hearing tests: 80.2 versus 43.3 tests/1,000 neonates, respectively (p = 0.026). Univariate analysis showed that late prematurity and age at 1st OAE were significantly associated with failure on 1st OAE. At age 24-42 h, failure on 1st OAE was 2-fold higher in the LP-ET infants than in full-term infants: 9.4 versus 4.7% (p = 0.02). Risk for failure on 1st OAE was age-dependent: 9-fold higher when 1st OAE was performed at 24-42 h of age (5.3%) versus 0.6% after age 42 h. Multivariate analysis showed that variables that were independently significantly associated with failure on 1st OAE included late prematurity (OR 2.0 (1.1-3.7)) and age at 1st OAE (OR 9.2 (1.2-70.7)). <b><i>Conclusions:</i></b> Compared to term infants, VD LP-ET infants had 2-fold higher rates of failure on 1st OAE (up to 42 h of life) and needed repeated hearing tests. Failure rates after 42 h become negligible in both groups. In VD LP-ET infants, 1st OAE is better performed after 42 h of age.