Objective:To reduce gastroesophageal reflux, infants are commonly placed in an inclined position. We sought to observe the extent to which infants exhibit (1) oxygen desaturation and bradycardia in supine and inclined positions and (2) signs and symptoms of post-feed regurgitation in these positions.Study Design:Healthy infants aged 1–5 months with gastroesophageal reflux disease (GERD) (N = 25) and controls (N = 10) were enrolled into one post-feed observation. Infants were monitored in a prototype reclining device for consecutive 15-minute periods in supine position with head elevations of 0°, 10°, 18°, and 28° in random order. Continuous pulse oximetry assessed hypoxia (O2saturation <94%) and bradycardia (heart rate <100). Regurgitation episodes and other symptoms were recorded. Mothers assessed comfort using an ordinal scale. Incident rate ratios were estimated using Poisson or negative binomial regression models.Results:Among infants with GERD, in each position, most had no episodes of hypoxia, bradycardia, or regurgitation. Overall, 17 (68%) infants had 80 episodes of hypoxia (median 20 seconds duration), 13 (54%) had 33 episodes of bradycardia (median 22 seconds duration), and 15 (60%) had 28 episodes of regurgitation. For all 3 outcomes, incident rate ratios were not significantly different between positions, and no differences were discovered for observed symptoms or infant comfort.Conclusions:Brief episodes of hypoxia and bradycardia as well as observed regurgitation are common for infants with GERD placed in the supine position after a feed with no differences in outcomes at various degrees of head elevation. These data may be used to power future, larger, and longer evaluations. ClinicalTrials.gov Identifier: NCT04542239.