Background and aims Prone supine sleeping-position has no impact on regurgitations in infants. Prone ventral decubitus decreases regurgitations but is associated with an increased risk of sudden infant death syndrome (SIDS). LUNE study aimed to evaluate the impact of regurgitations on the choice of sleeping-position by paediatricians and parents.

Methods Cross-sectional case-control study (ratio 1:1) conducted in France in 2012. A representative sample of paediatricians recruited 3 weeks to 4 months old breast- or formula-fed infants. Cases/controls were defined by presence/absence of regurgitations. Collected data included Vandenplas codification for regurgitations (VD, range 0–6), associated symptoms, treatments and sleeping position.

Results 1347 cases and 1346 controls were recruited by 493 paediatricians. Regurgitations were quoted VD1 (minor, 22% of cases); VD2 (light, 48% of cases) or VD≥3 (moderate to severe, 30% of cases). At maternity hospital 96% of parents have been recommended to put their infant to bed in supine position to prevent SIDS. Parents however have asked about the influence of sleeping position on regurgitations (79% of cases versus 44% of controls), and have modified at least once the sleeping-position (41% of cases versus 35% of controls). At entry in the study, 86% of cases and 86% of controls were resting on back. 51% of cases and 28% of controls slept in prone-position. Paediatricians repeated the prescription of dorsal decubitus for 91% of cases and recommended prone position in 69%.

Conclusions Regurgitations had no impact on supine sleeping-position.

Prone sleeping-position was more frequent in infants with regurgitations with paediatricians assent.